Abstract The Z-disk is a sophisticated structure that connects adjacent sarcomeres in striated muscle myofibrils. α-Actinin provides strength to the Z-disks by crosslinking the actin filaments of adjacent sarcomeres. α-Actinin is an antiparallel homodimer, composed of an N-terminal actin binding domain (ABD), the central rod domain, and two pairs of C-terminal EF-hands. The PDZ-LIM domain proteins interact with α-actinin at the Z-disk. Of these proteins, only the actinin-associated LIM protein (ALP), Z-band alternatively spliced PDZ-containing protein (ZASP/Cypher) and C-terminal LIM protein (CLP36) have a ZASP/Cypher-like (ZM) motif consisting of 26-27 conserved residues in the internal region between the PDZ and LIM domains. The aim of this work was to understand the molecular interplay between the ZM-motif containing members of the PDZ-LIM proteins and α-actinin. To unveil the biological relevance of the interaction between the PDZ-LIM proteins and α-actinin, naturally occurring human ZASP/Cypher mutations were analyzed. Two interaction sites were found between ALP, CLP36 and α-actinin using recombinant purified proteins in surface plasmon resonance (SPR) analysis. The PDZ domain of ALP and CLP36 recognized the C-terminus of α-actinin, whereas the internal regions bound to the rod domain. Further characterization showed that the ALP internal region adopts and extended conformation when interacting with α-actinin and that the ZM-motif partly mediated the interaction, but did not define the entire interaction area. ZASP/Cypher also interacted and competed with ALP in binding to the rod domain. The internal fragments containing the ZM-motif were important for co-localization of ALP and ZASP/Cypher with α-actinin at the Z-disks and on stress fibers. The absence of ALP and ZASP/Cypher in focal contacts indicates that other interacting molecules, for instance vinculin and integrin, may compete in binding to the rod in these areas or additional proteins are required in targeting to these locations. The co-localization of the ZASP/Cypher with α-actinin could be released by disrupting the stress fibers leading to an accumulation of α-actinin in the cell periphery, whereas ZASP/Cypher was not in these areas. This suggests that an intact cytoskeleton is important for ZASP/Cypher interaction with α-actinin. Earlier studies have shown that mutations in the ZASP/Cypher internal region are associated with muscular diseases. These mutations, however, did not affect ZASP/Cypher co-localization with α-actinin or the stability of ZASP/Cypher proteins. The Z-disk possesses a stretch sensor, which is involved in triggering hypertrophic growth as a compensatory mechanism to increased workloads. α-Actinin is a docking site of molecules that are involved in hypertrophic signaling cascades mediated by calsarcin-calcineurin and protein kinase C (PKC) isoforms. The internal interaction site may be involved in targeting PKCs, which bind to the LIM domains of ZASP/Cypher, to the Z-disks. The similar location of the internal interaction site with calsarcin on the rod suggests that ZASP/Cypher, ALP and CLP36 may regulate calsarcin-mediated hypertrophic signaling.

Greitumas – vienas iš svarbiausių judamųjų gebėjimų. Jis įvairiose sporto šakose pasireiškia skirtingomis formomis. Greitumo pratybos, tai tokios pratybos, kurios nemažina maksimalaus raumens susitraukimo ir atsipalaidavimo greičio, o jį padidina. Yra žinoma, kad jėgos pratybos yra kenksmingos greitumui. Mūsų nuomone, didžiausia problema sporto moksle - kaip padidinti jėgą nesumažinant raumens susitraukimo ir atsipalaidavimo greičio. Taip pat labai aktualu sužinoti, kaip skirtingų genų variantų žmonės geba didinti greitumą ir jo pasireiškimo formas. Šiuo metu pasirodė daug straipsnių apie ACTN3 R577X polimorfizmą. Yra žinoma, kad α-aktinino-3 baltymo nėra pas 16 % pasaulio žmonių. Įdomu tai, kad mutavusio (X) alelio ir ypač pilno α-aktinino-3 (alelis XX) deficito dažnis yra ženkliai mažesnis tarp sprinto ir galingumo atletus. Todėl mes savo tyrime analizavome greitumo pratybų įtaką didesnio jėgos indėlio reikalaujantiems pratimams ir gautus rezultatus lyginome tarp skirtingų RR ir XX genotipų. Tyrimo tikslas – ištirti maksimalaus greitumo padidėjimo įtaką didesnio jėgos indėlio reikalaujantiems judamiesiems gebėjimams priklausomai nuo RR (gaminasi α-aktininas-3) ir XX (nesigamina α-aktininas-3) genotipo. Tyrimo objektas – greitumo pokytis ir to pokyčio įtaka didesnės jėgos reikalaujantiems judamiesiems gebėjimams RR ir XX genotipo grupėse. Tyrimo uždaviniai: 1. Nustatyti ir įvertinti, kaip po 10 maksimalaus greitumo lavinimo pratybų kito RR ir XX grupių greitumo judamasis... [toliau žr. visą tekstą] / Running speed is one of the most important physical properties. It has various forms. Speed training does not decrease muscle contraction and relaxation speed. It is well known, that strength training decrease running speed results. That’s why we think that maybe the most important problem in sport science is how to increase strength without maximum muscle contraction and relaxation speed decrease. Also it is important to know how people with different genotypes can increase running speed. There are only few articles about ACTN3 R577X polymorphism. A common nonsense mutation (R577X) in the ACTN3, resulting in a premature stop codon and lack of detectable protein in homozygous individuals for the ACTN3 null allele (XX genotype), has been demonstrated in the general human population with 16 % prevalence in Caucasians. Sprint athletes have lower 577XX genotype frequency endurance athletes. That’s why we analyze running speed workouts influence to more strength required physical properties between RR and XX groups. The aim of the study - to investigate running speed increment influence to more strength required physical properties and compare results between RR (with α-actinin-3) and XX (without α-actinin-3) groups. The object of the study - running speed change and this change influence to more strength required physical properties between RR (with α-actinin-3) and XX (without α-actinin-3) groups. Study tasks: 1. To investigate how after maximum speed workouts vary running speed... [to full text]

Nephrotic syndrome (NS) is characterized by proteinuria, hypalbuminemia and edemas. It occurs during first and second glomerulopathies. This disease can be divided into two groups: primary (idiopathic) and secondary. The heredity of the familial nephrotic syndrome is autosomal dominant and autosomal recessive. There are four most important genes that condition the formation of hereditary nephrotic syndrome in adult patienst. These genes are ACTN4, CD2AP, NPHS2 and TRPC6. The gene ACTN4, which encodes protein α-actinin 4, is responsible for the autosomal dominant form of focal segmental glomerulosclerosis (FSGS). FSGS is included in first glomerulopathies. α-Actinin 4 was also researched for some types of carcinomas. There was performed the mutational analysis of the gene ACTN4 on the set of 48 patients with nephrotic syndrome in this diploma thesis. High resolution melting (HRM) analysis and sequencing selected samples were used during this mutation detection. During this process many published and unpublished SNPs and one unpublished candidate mutation that could have causal associations with FSGS were found.