Les septines sont une famille de protéines GTPases qui peuvent former des structures d'ordre supérieur, comme les filaments et les anneaux, et capables de se lier avec les membranes cellulaires par leur interaction avec les phosphoinositides (PIs) via un domaine polybasique en N-terminal de leur domaine de liaison au GTP. Nous avons montré par une analyse transcriptomique réalisée en utilisant les données GSE14323 que la septine 9 est significativement surexprimée dans la cirrhose induite par le virus de l'hepatite C (VHC). Nos résultats montrent, ainsi, que la septine 9 induit l’augmentation en taille des gouttelettes lipidiques (GLs) par un mécanisme dépendant le phosphatidylinositol-5-phosphate et des microtubules. Nous avons montré, également, que cette voie de régulation des GLs est exploité par le VHC. De plus, nous avons montré que la septine 9 est impliquée dans la régulation de la morphologie de l’appareil Golgi et la mise en place de la polarité cellulaire par son interaction avec les phosphoinositides via deux domaines polybasiques. Ces résultats apportent une nouvelle compréhension du mécanisme moléculaire de l’interaction des septines avec les phosphoinositides et montrent pour la première fois l’importance de cette interaction dans des fonctions cellulaires de la septine 9. / Septins are a GTPases proteins family that can form high order structures such as filaments and rings, and able to bind cell membranes by interacting with phosphoinositides via a polybasic domain located at the N-terminal of their GTP binding domain. Here, We show by the transcriptomic analysis performed using the GSE14323 dataset that septin 9 is significantly upregulated in hepatitis C virus induced cirrhosis. Our findings show that septin 9 induce the lipid droplet growth by a phosphatidylinositol-5-phosphate and microtubule-dependent mechanism hijacked by HCV. In addition, we have shown that the septin 9 is involved in Golgi apparatus morphology regulation and cell polarity installation by interacting with phosphoinositides via two polybasic domains. These results provide new understanding of the molecular mechanism of septins interaction with the phosphoinositides and show its importance in septin 9 cellular functions shown for the first time.

The Golgi apparatus is the main crossroad of the intracellular trafficking network in all eukaryotic cells and plays a crucial role in the distribution of cellular material. To ensure the proper sorting and delivery of cargo proteins to their destination while maintaining Golgi homeostasis the coordination of all transport events to and from this organelle is required. Although a cascade of activation events has already been reported for Golgi Ypt/Rab proteins that function in the exocytic pathway, their connection to incoming vesicles from endosomal compartments or to the different Arf mediated vesicle formation machineries has still to be established. In addition, the role of lipids and the interplay between lipid and protein regulators at the Golgi are largely missing. In the present study, we used several approaches to unravel the crosstalk between known regulators of Golgi trafficking and to identify new proteins involved in this process. As starting point, we considered the results from four different screens before focusing on the role of Arf exchange factors. We report two new physical interactors of the late Golgi Arf-GEF Sec7p: the lipid kinase Pik1p and the cyclic nucleotide phosphodiesterase Cpd1p. In addition, our studies on the function of Sec7p revealed additional feature of this protein and it’s relationship to the other yeast Golgi Arf-GEFs. Arf proteins and their regulators play an important role in the formation of vesicles at the exit from the Golgi apparatus. There are three Golgi-localized Arf-GEFs in S.cerevisiae, Sec7p and the redundant Gea1p/Gea2p. While it has been established that Sec7p function does not overlap with the Gea’s, the specific role of these proteins remains unclear. We show that Sec7p colocalizes poorly with the Gea’s, indicating that these proteins activate Arf on different Golgi sub-compartments. In addition, our data suggest that Sec7p mainly promotes the formation of post-Golgi transport vesicles supporting forward transport from the late Golgi while the Gea’s primarily regulate COPI-mediated retrograde traffic. This observation is consistent with published data from mammalian cells and suggests that the spatial and temporal regulation of Arf is conserved from yeast to mammals. Both Arf regulation and phosphatidylinositol 4-phosphate (PI4P) metabolism are important factors for Golgi function. Here, we show that the yeast PI4-kinase, Pik1p binds specifically to Sec7p but not Gea1p or Gea2p. Taken together, the physical interaction, the colocalization and similar transport phenotypes of the respective mutants suggests a functional link between Pik1p and Sec7p but not the Gea’s. In addition, Pik1p binds to the catalytic domain of Sec7p and could directly influence the activity of the GEF. We propose that this interaction coordinates Arf activation with PI4P production to generate a highly specific dual recognition system for the recruitment of specific effectors to the late Golgi. Besides its catalytic domain, Sec7p shares several conserved regions with other members of the BIG/GBF Arf-GEF subfamilies, including the N-terminal DCB (Dimerization/Cyclophilin Binding) domain. We show that a single point mutation in the DCB domain of Sec7p efficiently inhibits Arf activation without affecting membrane recruitment of the GEF and could interfere with a possible dimerization of the protein. We identified Cpd1p as an allele specific dosage suppressor of the Sec7p DCB domain mutation. Cpd1p and Sec7p physically interact and both proteins localize independently to the late Golgi. Increased Golgi level of Cpd1p compensates for the loss of interaction due to the mutation in the DCB domain of Sec7p. The catalytic activity of Cpd1p is important for the rescue, indicating an intriguing connection between the Arf activation cycle and ADP-ribose derivates. We also find that Cpd1p interacts with several other proteins involved in Golgi- and post-Golgi transport events. Hence, Cpd1p is a new regulator of vesicular traffic at the Golgi that could act as a scaffolding factor for Sec7p and other transport proteins.

Chlamydien sind obligat intrazelluläre Bakterien, die sich in einem membranumschlossenen Kompartiment namens Inklusion vermehren. Nach Infektion fragmentiert der Golgi-Apparat der Wirtszelle in kleine Membranstapel. Dies verbessert die Aufnahme von Sphingolipiden und ist deshalb für die chlamydiale Vermehrung essentiell. Die infektionsinduzierte Golgi-Fragmentierung geschieht nach Spaltung des Golgi-Matrix-Proteins Golgin-84. In dieser Arbeit konnte, durch den Vergleich mit bekannten Substraten und Inhibitorstudien, die chlamydiale Protease CPAF (Chlamydia protease-like activity factor) als das Enzym identifiziert werden, das diese Spaltung induziert, abhängig von der Anwesenheit zweier Rab-Proteine, Rab6 und Rab11, die den zellulären Vesikeltransport kontrollieren und zur Inklusion rekrutiert werden. Die Fragmentierung des Golgi-Apparates verhinderte dessen Relokalisierung während der Zellpolarisierung nach Einbringen eines migratorischen Stimulus. Sowohl infizierte als auch Golgin-84-depletierte Zellen migrierten langsamer und randomisiert in einem Motilitätsassay. Die Relokalisierung des Golgi-Apparates konnte durch seine Stabilisierung mittels WEHD oder Rab-Depletion wieder gewonnen werden, was die Zellmotilität teilweise wieder herstellte. Darüber hinaus konnte gezeigt werden, dass die Infektion außer der Golgi-Reorientierung die Signaltransduktion durch GTPasen beeinflusst. Die Aktivität von Cdc42 in infizierten Zellen war erhöht und die Interaktionen mit vielen ihrer Effektoren laut quantitativer Massenspektrometrie stark verändert. Die Ergebnisse dieser Arbeit zeigen, dass CPAF die für Chlamydien lebenswichtige Golgin-84 Prozessierung und Fragmentierung des Golgi-Apparates auslöst. Dies verringert die Mobilität der Wirtszelle, vor allem da der Golgi-Apparat während der Polarisierung nicht mehr ausgerichtet werden kann, des Weiteren durch Modulierung der Protein-Protein-Interaktionen von Cdc42. / Chlamydia are obligate intracellular human pathogens that proliferate inside a membrane-bound compartment called the inclusion. In infected cells, the Golgi apparatus is fragmented into small ministacks that are aligned around the inclusion. This facilitates uptake of host cell sphingolipids and is essential for chlamydial development. Infection-induced Golgi fragmentation happens after processing of the Golgi matrix protein golgin-84. This work could, via comparison with well-known substrates and inhibitor studies, identify the chlamydial protease CPAF (Chlamydia protease-like activity factor) as the enzyme accountable for this cleavage. Golgi Fragmentation depended on two Rab proteins, Rab6 and Rab11, which control vesicle transport and are recruited to the Chlamydia inclusion. As a consequence of Golgi fragmentation, cells lost the capacity to reorient the Golgi apparatus during polarization after a migratory stimulus. Both infected and golgin-84 depleted cells with a permanently fragmented Golgi apparatus displayed decelerated and furthermore randomized migration in a motility assay. Relocalization of the Golgi apparatus could be restored via stabilizing WEHD treatment or Rab depletion which partly rescued cell motility. Moreover, it could be shown that migration signaling via small GTPases was influenced by Chlamydia infection. Infected cells exhibited activation of the small polarity GTPase Cdc42. Numerous interactions with downstream effectors were strongly altered in infected cells according to quantitative mass spectrometry. Particularly, the binding of Cdc42 to migration-associated effectors was decreased. The results of this work show that CPAF, by processing of golgin-84, induces Golgi fragmentation which is vitally important for Chlamydia. This disturbs host cell motility because the Golgi apparatus cannot be reoriented during polarization and, additionally, via the modulation of protein-protein-interactions of Cdc42.

In Saccharomyces cerevisiae, experiments with temperature-sensitive mutants of the PI4-kinase Pik1p revealed that the PI4P pool generated by this enzyme is essential for Golgi morphology and normal secretory function and that the PI4P pool at the Golgi represents a regulatory signal on its own. In order to function as a spatial and temporal regulator of membrane traffic, PI4P synthesis and turnover must be tightly regulated. It remains elusive which factors are involved in the targeting and regulation of Pik1p. Little is also known about PI4P binding proteins mediating the effects of this phosphoinositide on Golgi function. Since it has been shown that multiple pathways leave the Golgi towards the plasma membrane one can ask the question whether Pik1p and its product PI4P specifically control one pathway? Here we demonstrate an interaction of Pik1p with the 14-3-3 proteins Bmh1p and Bmh2p. Interestingly, overexpression of Bmh1p and Bmh2p results in multiple genetic interactions with genes involved in late steps of exocytosis and it affects the forward transport of the general amino acid permease Gap1p. The detected interaction depends on the phosphorylation state of Pik1p and Pik1p phosphorylation accompanies its shuttling out of the nucleus into the cytoplasm where presumably the binding to Bmh1/2p occurs. Therefore, we reason that these interactions might serve the sequestration of Pik1p away from the Golgi. This study reveals that Pik1p shows a strong effect on the delivery of Gap1p to the surface whereas the transport of exocytosis markers implicated in the direct Golgi-to-plasma membrane pathway are not significantly disturbed. Cells carrying a deletion of gga2 also show a strong defect in delivery of Gap1p to the surface. In addition, pik1-101 gga2[delta]double mutants display synthetic genetic and membrane transport phenotypes and recruitment of Gga2 to the TGN partially depends on functional Pik1p. Therefore, our results suggest a role of Pik1p in the TGN to endosome pathway.

No description available.

Nhx1 est un antiport vacuolaire de Na+/H+ chez la levure Saccharomyces cerevisiae. Nhx1 joue un rôle important dans le maintien de l’homéostasie ionique du cytoplasme de la cellule. En effet, la mutation du gène NHX1 chez la levure nhx1Δ entraîne une perte de l’homéostasie cellulaire quand les cellules sont cultivées dans un milieu de faible osmolarité. Ce travail rapporte pour la première fois, et contrairement à la cellule parentale, que la mutation du gène NHX1 a pour effet une sensibilité du mutant nhx1Δ à une variété des drogues et des agents cationiques et anioniques lorsque les cellules sont cultivées dans un milieu riche. En outre, dans ces conditions de culture, aucune sensibilité n’a été observée chez le mutant nhx1Δ quand les cellules sont traitées avec différentes concentrations de sel. Nous avons aussi démontré que la sensibilité du mutant nhx1Δ aux différents agents ainsi que la sécrétion de l’enzyme carboxypeptidase Y observé chez ce mutant n’ont pas été restauré lorsque les cellules sont cultivées dans des milieux avec différents pH ou avec différentes concentrations de sel. Enfin, une analyse génétique a révélé que le mutant nhx1Δ montre un phénotype distinct d’autres mutants qui ont un défaut dans le trafic entre le compartiment pré-vacuolaire et l’appareil de Golgi quand ces cellules sont traitées avec différents agents. Cette analyse prouve que la sensibilité de nhx1Δ aux différents agents n’est pas liée au trafic entre le compartiment pré-vacuolaire et l’appareil de Golgi. / Nhx1 is an intracellular Na+/H+ exchanger localized to the late endosome in Saccharomyces cerevisiae. It is believed that Nhx1 plays a major role in pH-mediated vesicle trafficking, as nhx1Δ mutant is defective in maintaining the intracellular pH in the vacuoles and cytoplasm when grown in low osmolarity media. In this work, we reported novel drug sensitivities of the nhx1Δ mutant to a range of cationic and anionic agents when cells are grown in rich media. Unlike the low osmolarity media, the nhx1Δ mutant showed no sensitivity to salt. Furthermore, we showed that the drug phenotypes of the nhx1Δ mutant, as well as the secretion of the vacuolar protein carboxypeptidase Y, were not rescued by either altering the pH or salt concentration. Although, amino acid substitution of the phylogenetically conserved residue Glu355 for Ala (E355A) in Nhx1 resulted in sensitivity to genotoxic drug bleomycin, it was not observed for the non-conserved residue Glu371Ala (E371A). Moreover, genetic analysis revealed that the nhx1Δ mutant displayed distinct drug phenotypes in comparison to mutants that are defective in retrograde trafficking from the prevacuole to the late Golgi, excluding the possibility that the drug sensitivity of the nhx1Δ mutant is related to retrograde trafficking.

Mouse polyomavirus (MPyV) is a model virus of the Polyomaviridae family. Polyomaviruses are small non-enveloped DNA viruses. They cause severe problems to immunocompromised patients. Their oncogenic potential is known in animals and humans. Trafficking of MPyV within the cell is not clear yet. The virus enters via smooth monopinocytic vesicles and continues to early and late endosomes. From there, the virus is transported to the ER by unknown mechanism. It bypasses Golgi aparatus (GA). One possible pathway is from late endosomes to trans-Golgi network (TGN) facilitated by Rab9 GTPase and then in COPI vesicles to the ER. In this thesis, the effect of inhibitors of retrograde transport (Brefeldin A, Golgicide A) on MPyV infection was evaluated. Brefeldin A is not completely specific; it has effect on whole endosomal system. Golgicide A causes specific disruption of transport via TGN and GA. Both inhibitors suppressed infection of MPyV. Confocal microscopy revealed colocalization of some MPyV virions with markers of TGN and COPI vesicles. MPyV didn't colocalize with cis-Golgi marker. Unfortunately, the effect of overexpression of Rab9 dominant negative mutant couldn't been evaluated due to its high cytotoxicity. However, overexpression of wild type Rab9 slightly increased infectivity. The results...

Les protéines SNARE (Soluble N-ethylmaleimide-sensitive factor Attachment protein REceptor) sont essentielles pour la fusion membranaire. J'ai étudié chez Arabidopsis thaliana la SNARE Memb11 de l’appareil de Golgi qui intervient au début de la voie sécrétoire à l'interface Réticulum endoplasmique (RE)-appareil de Golgi. Dans les cellules de mammifères, l'orthologue de Memb11 (Membrine) est un « récepteur » potentiel de la GTPase Arf1 à la membrane golgienne. Cette dernière est impliquée dans le recrutement de la machinerie COPI nécessaire au transport rétrograde de l'appareil de Golgi vers le RE. Le but de ce travail était de déterminer si Memb11 pouvait interagir avec Arf1 dans les cellules végétales. Des anticorps dirigés contre la partie cytosolique de Memb11 ont été obtenus et ont été utilisés sur tissus végétaux pour réaliser des immunomarquages en microscopie électronique à transmission et des immunoprécipitations sur extraits de plantes. Il a été démontré que Memb11 est située au niveau de la membrane cis-golgienne et qu'elle co-immunoprécipite avec Arf1, suggérant ainsi que Arf1 peut interagir avec Memb11. J'ai confirmé l'interaction de Memb11 et Arf1 au niveau de l'appareil de Golgi par des expériences de BiFC (Bimolecular Fluorescence Complementation) in vivo. Cette interaction est spécifique puisque ni Memb12 (90% d'identité avec Memb11) ni Sec22 interagissent avec Arf1. Grâce à une approche de bioinformatique structurale, j'ai déterminé les régions de Memb11 (différentes de Memb12) qui pourraient être critiques pour l'interaction et j’ai commencé à tester in vivo les mutants correspondants par BiFC. En outre, des expériences d’immunoprécipitations avec des protéines recombinantes produites in vitro suggèrent que la forme d’Arf1 liée au GTP interagit avec Memb11. / The SNARE proteins (Soluble N-ethylmaleimide-sensitive factor Attachment protein REceptor) are critical for membrane fusion in the secretory pathway. I have studied the Golgi SNARE Memb11 in Arabidopsis thaliana cells. Memb11 is involved at the ER-Golgi interface. In mammalian cells, the ortholog of Memb11 (Membrin) is the potential “receptor” of the GTPase Arf1 in the Golgi membrane. This protein is involved for the recruitment of the COPI machinery, required for retrograde transport from the Golgi to the ER. The aim of this work was to determine whether Memb11 can interact with Arf1 in plant cells. Antibodies against the cytosolic part of Memb11 were obtained and were applied on plant tissues to perform immunolabeling by transmission electron microscopy and immunoprecipitation (IP) studies. It has been shown that Memb11 is located at the cis-Golgi and that it co-immunoprecipated with Arf1, suggesting that Arf1 may interact with Memb11. I confirmed the interaction of Memb11 and Arf1 at the Golgi by in vivo BiFC (Bimolecular Fluorescence Complementation) experiments. This interaction was specific since neither Memb12 (90% identity with Memb11) nor Sec22 interacted with ARF1. Thanks to a structural bioinformatic approach, I determined the regions in Memb11 (different from Memb12) that could be critical for the interaction and started to test corresponding mutants in vivo by BiFC. In addition, IP experiments with recombinant proteins produced in vitro suggest that the GTP-bound form of ARF1 interacts with Memb11.

Weltweit kommt es jährlich zu 90 Mio. Neuinfektionen mit dem sexuell übertragbaren Erreger Chlamydia trachomatis. Allerdings sind die Faktoren, die eine erfolgreiche bakterielle Vermehrung ermöglichen, weitgehend unbekannt. Während ihrer obligat intrazellulären Entwicklung sind Chlamydien auf die Errichtung und Erhaltung ihrer Nische, der Inklusion, angewiesen. Durch Interaktionen mit vesikulären Transportwegen der Wirtszelle, welche z.B. Sphingolipide transportieren, sichern die Bakterien ihr Überleben. In der vorliegenden Arbeit konnte gezeigt werden, dass Chlamydien während einer Infektion die Auflösung der Struktur des Golgi-Apparates induzieren. Mit Hilfe der RNA-Interferenz-Technik (RNAi) wurden die Auswirkungen des Verlustes von Golgi-Strukturproteinen auf die bakterielle Vermehrung untersucht. Der funktionelle Ausfall von Golginen, wie z.B. Golgin-84 führte zu einer Fragmentierung des Golgi-Apparates. Diese begünstigte die chlamydiale Produktion neuer infektiöser Partikel, was eine verbesserte Versorgung mit Nährstoffen nahelegt. Im vesikulären Transport von Nährstoffen übernehmen Rab-Proteine eine Schlüsselrolle. Interessanterweise konnte in dieser Arbeit gezeigt werden, dass der Verlust von Rab6 und Rab11 durch RNAi zu einer signifikanten Verringerung der Anzahl infektiöser Nachkommen führte. In diesen Zellen wurde der Golgi-Apparat nicht fragmentiert und der Transport von Sphingolipiden zu den Bakterien war stark vermindert. Untersuchungen nach simultaner Herunterregulation von Golgin-84 und Rab6 oder Rab11 demonstrierten abschließend, dass eine Kontrolle der Golgin-84-induzierten Golgi-Fragmentierung über Rab-Proteine möglich sein könnte. Die Ergebnisse dieser Arbeit offenbaren einen neuen Zusammenhang zwischen der Struktur des Golgi-Apparates und dessen Kontrolle über Rab-Proteine und ermöglichen einen tieferen Einblick in die Funktion des Golgi-Apparates während einer Chlamydien-Infektion. / Worldwide, approximately 90 mio. people are infected with the obligate intracellular bacterium Chlamydia trachomatis. However the factors involved in its successful infection and replication remain unknown. Chlamydia survive and replicate within a membrane bound niche inside host cells, termed the inclusion. To ensure survival, the chlamydial inclusion intercepts vesicular trafficking pathways of the host cell to acquire essential nutrients, such as sphingolipids. However, the exact mechanisms by which Chlamydia acquire these lipids have not been elucidated. The present work established that infection of host mammalian cells with C. trachomatis induced fragmentation of the Golgi-apparatus, but details of the mechanism to the bacterium’s pathogenesis are still required. Using RNA-Interference the role of specific Golgi-apparatus structural proteins in bacterial infectivity was investigated. Knockdown of Golgins in host cells resulted in a fragmented Golgi-apparatus and an associated increase in chlamydial replication, suggesting an enhanced acquisition of nutrients. Since Rab-proteins are known to co-ordinate the intracellular vesicular transport of nutrients, their importance in chlamydial infectivity was also investigated. Interestingly, knock down of Rab6 and Rab11 led to a significant reduction in infectious progeny. Surprisingly, upon knock down of Rab6 or Rab11 the Golgi-apparatus remained intact and sphingolipid transport into the inclusion was severely perturbed. Finally, analysis of cells simultaneously depleted of golgin-84 and Rab6 or Rab11 suggested a possible role of Rab-proteins in the control of golgin-84-induced Golgi fragmentation. These data demonstrate a yet unknown relationship between the structure of the Golgi-apparatus and its regulation and control by Rab-proteins. Furthermore, this work contributes to the existing knowledge regarding the function of the Golgi-apparatus during chlamydial infections.

O encéfalo humano é mais sofisticado instrumento de cognição e, supostamente, o material mais complexo já conhecido, provavelmente por causa disso, o sistema neural é amplamente estudado em termos multidisciplinares, mas muitas questões ainda necessitam ser respondidas e várias dúvidas sobre as funções cerebrais ainda precisam de respostas. Um dos caminhos para compreender essa história evolutiva é o estudo do encéfalo de primatas não-humanos. Muito se sabe sobre a anatomia macroscópica de primatas do Velho Mundo e humanos, entretanto, esses dados e aqueles relacionados à anatomia microscópica são escassos em relação aos neotropicais, que tem sido amplamente utilizado em pesquisas biomédicas e comportamentais. Dessa forma, a proposta desse trabalho foi estudar a anatomia macroscópica do encéfalo obtido diretamente dos primatas neotropicais como Callithrix penicillata, Saimiri ustus, Sapajus libidinosus e Brachyteles arachnoides e da literatura de Galago, Macaca, Papio, Pan and Homo, em termos comparativos. Além de realizar um estudo preliminar acerca da citoarquitetura neocortical de Sapajus libidinosus. Na análise macroscópicas foram utilizados 2 encéfalos de Callithrix penicillata, 1 de Saimiri ustus, 7 de Sapajus libidinosus e 1 Brachyteles arachnoides, que tiverem seus sulcos e giros descritos, mensurados, além de mensurações das dimensões gerais do encéfalo e índice de encefalização. Para a análise microscópica foram utilizados 5 encéfalos de Sapajus libidinosus, sendo 4 na técnica de Golgi-Cox e 1 na técnica HE, que foram avaliados em termos de organização citoarquitetônica, número de células neurais e classificação do córtex conforme o tipo e prevalência celular nas camadas corticais, dos lobos frontal, área pré-frontal, parietal, temporal e occipital. Nesse trabalho observou-se que anatomia do telencéfalo de Callithrix e Saimiri possuem poucos sulcos, giros quando comparados com o de Sapajus e Brachyteles e os dois últimos são mais semelhantes aos primatas do Velho Mundo, do que dos demais primatas neotropicais investigados. Dentre todos os primatas analisados e comparados, os sulcos que se repetem são o longitudinal, lateral, calcarino, hipocampo, rinal e o temporal superior. Os sulcos do lobo frontal e parietal, aparecem somente em encéfalos mais complexos e de animais que possuem maior tamanho corporal. As demais estruturas localizadas na região medial do telencéfalo, diencéfalo, mesencéfalo, ponte, bulbo e ventrículos encefálicos, estão dispostas de forma semelhante com variações no grau de desenvolvimento e tamanho. Os dados preliminares da arquitetura neocortical de Sapajus mostram maior quantidade de neurônios nos lobos occipital, seguidos do parietal e temporal. A parte caudal do lobo frontal possui carcterísticas de área motora primária com grandes neurônios piramidais e a área pré-frontal possui prevalência de neurônios granulares. Os lobos parietal e temporal possuem as camadas mais heterogêneas e com maior separação entre as camadas corticais. A técnica de Golgi- Cox permitiu estudar a organização estrutural, conexões entre células neurais e a formas das células neurais. Já a técnica de HE permitiu inferências quantitativas e também a caracterização dos tipos de células neurais e desenvolvimento das camadas corticais. As análises histológicas do neocórtex das principais áreas do telencéfalo de Sapajus libidinosus, mesmo que com um baixo número de espécimes foi uma caracterização geral e o primeiro passo para estudos futuros e comparações mais abrangentes. São necessários estudos histológicos mais detalhados das principais áreas do encéfalo, assim como a associação dos possíveis resultados a outras técnicas de investigações são necessários para uma melhor caracterização das funcionalidades das áreas corticais. / The human brain is the most sophisticated instrument of cognition and, putatively, the most complex material sctructure ever knew, probably because that, the neural system is largely studied in multidisciplinar terms, but many questions still need to be answered and various doubts rest to be solved about the brain functions. Among the ways to understand this evolutionary history is the study of the non-human primate encephalon. Much is known about the gross anatomy of Old World Primates and humans, however, these data and those related to the microscopic anatomy are scarce compared to the neotropical, which has been widely used in biomedical and behavioral research. In order, the purpose of this work was to study the gross anatomy of the brain obtained from neotropical primates as Callithrix penicillata, Saimiri ustus, Sapajus libidinosus e Brachyteles arachnoides and from literature from Galago, Macaca, Papio, Pan and Homo, in comparative terms. In addition to conducting a preliminary study on the neocortical cytoarchitecture of Sapajus libidinosus. In gross anatomy were used 2 brains of Callithrix penicillata, 1 of Saimirius ustus, 7 of Sapajus libidinosus and 1 Brachyteles arachnoides, which have their sulcus and gyri described, measured, as well as measurements of the general dimensions of the encephalon and encephalization index. For the microscopic analysis, 5 brains of Sapajus libidinosus were used, 4 in the Golgi-Cox method and 1 in the HE method, which were evaluated in terms of cytoarchitectonic organization, number of neural cells and classification of the cortex according to type and cell prevalence in cortical layers, frontal, prefrontal area, parietal, temporal and occipital areas. In this study, it was observed that the gross anatomy telencephalon of Callithrix and Saimiri have few sulcus and gyri when compared to Sapajus and Brachyteles, and the latter two are more similar to the Old-World primates than of the other neotropical primates investigated. Among all the primates analyzed and compared, the repeats sulcus are the longitudinal, lateral, calcarino, hippocampus, rinal and superior temporal sulci. The sulci of the frontal lobe and parietal lobe appear only in more complex brains and animals that have larger body size. The other structures located in the medial region of the telencephalon, diencephalon, midbrain, pons, bulb and encephalic ventricles are similarly arranged with variations in the degree of development and size. Preliminary data from Sapajus neocortical architecture show higher numbers of neurons in the occipital lobes, followed by the parietal and temporal lobes. The caudal part of the frontal lobe has features of primary motor area with large pyramidal neurons and the prefrontal area has a prevalence of granular neurons. The parietal and temporal lobes have the most heterogeneous layers and with greater separation between the cortical layers. The Golgi-Cox method allowed the study of the structural organization, connections between neural cells and neural cell forms, and the HE method allowed quantitative inferences and also the characterization of neural cell types and development of the cortical layers. The histological analyzes of the neocortex of the main areas of the Sapajus libidinosus telencephalon, even with a low number of specimens, was a general characterization and the first step for future studies and more comprehensive comparisons. More detailed histological studies of the main areas are necessary as well the association of these possibles results with other investigative techniques for a better characterization of the functionalities of the cortical areas.