In this thesis, the overall purpose was to investigate the role of regulation in the care of older people with depression living in long-term care (LTC). The first manuscript in this thesis is a systematic scoping review protocol which was published in BMJ open, using Arksey and O'Malley's scoping review methodology as a guide. In the second manuscript which was submitted to BMC Geriatrics, a systematic scoping review was conducted, exploring the concepts of regulation, older people, depression, and long-term care. The search yielded 778 unique articles, of which 21 were included in the final analysis. The scoping review revealed that the highly regulated environment of LTC poses significant challenges which can influence the quality of care of residents with depression. Despite evidence of high prevalence and improved treatment, regulation appears to have failed to capture best practice and contemporary knowledge. The scoping review demonstrated a need for further empirical research to explore these issues. Findings from this study, which explored the role of regulation on the quality of care of older people living with depression in LTC are presented, and which were the basis of the third manuscript, to the Canadian Journal of Aging. Using instrumental case study methodology, I interviewed managers, staff, informal carers and residents, and reviewed documents and clinical charts. I found that Ministry of Health and Long-Term Care regulations influenced strategic planning, educational priorities, resourcing decisions and direct care. The findings from the study suggest an alternative approach to regulation is needed in this sector, which places accountability for standards of care at a provincial level and which has a more supportive and collaborative approach to regulations. The research findings showed that the staff working in the LTC home are committed to the care of residents with depression, but they had little time to implement additional quality initiatives outside of the identified mandated areas. The study concludes by suggesting that in its current state, the care of residents with depression in LTC homes is not reflected in Ministry of Health and Long-Term Care regulations and inspections, which make little difference to the care of older people living with depression living in LTC. In contributing to the existing knowledge and practice the study along with the findings from the scoping review, finds an alternative model of inspection could be implemented in partnership with the province. An alternative approach to inspection might adopt an extended approach to quality, along with an individualized approach to inspections to meet the requirements set out in regulation, but at the same time offering flexibility and a more collaborative approach to improving quality in the LTC sector.

Neuroblastoma is a heterogeneous pediatric malignancy originating from the developing sympathetic nervous system, with poor long-term survival for high-risk patients (~40%). About half of advanced neuroblastomas harbor high-level amplification of the MYCN gene, and these tumors show few, if any, additional driver lesions. Despite significant increase in the body of knowledge of genetics in neuroblastoma, all the high-risk patients follow similar therapeutic procedures and little advancement has been made on molecular target based therapies. The major challenge is to dissect the complexity and heterogeneity of these tumors to find driver genes and activated pathways that are essential for the survival of these cancer cells. We used an integrated systems biology approach to define the core regulatory machinery responsible for maintenance of an aggressive neuroblastoma phenotypic state. In the first part of the thesis, I will discuss our computational approach to decipher the tumor heterogeneity by subtype classification, followed by identification of master regulator protein modules for three distinct molecular subtypes of high-risk neuroblastomas, which were validated in a large independent cohort of cases. We propose that such modules are responsible for integrating the effect of mutations in upstream pathways and for regulating the genetic programs and pathways necessary for tumor state implementation and maintenance. The second part of the thesis is focused on experimental validation of putative master regulators in the subtype of neuroblastomas associated with MYCN amplification. By using RNAi screening followed by experimental and computational analyses to elucidate the interdependencies between the top master regulators, we identified TEAD4-MYCN positive feedback loop as a major tumor maintenance mechanism in this subtype. While MYCN regulates TEAD4 transcriptionally, TEAD4 regulates MYCN through transcriptional and post-translational mechanisms. Jointly, MYCN and TEAD4 regulate 90% of inferred MR proteins and causally orchestrate 70% of the subtype-specific gene expression signature. TEAD4 gene expression was associated with neuroblastoma patient survival independently of age, tumor stage and MYCN status (P=2.1e-02). In cellular assays, MYCN promoted growth and repressed differentiation, while TEAD4 activated proliferation and DNA damage repair programs, the signature hallmarks of MYCN-amplified neuroblastoma cells. Specifically, TEAD4 was shown to induce MYCN-independent proliferation by transactivating key genes implicated in high-risk neuroblastoma pathogenesis, including cyclin-dependent kinases, cyclins, E2Fs, DNA replication factors, checkpoint kinases and ubiquitin ligases. The critical role of the core master regulator module in controlling tumor cell viability, both in vitro and in vivo, and its clinical relevance as a prognostic factor highlights TEAD4 as a novel and highly effective candidate target for therapeutic intervention. In this thesis, we demonstrate that interrogation of tumor specific regulatory networks with patient-derived gene expression signatures can effectively elucidate molecular subtypes as well as the core transcriptional machinery driving subtype specific hallmarks. This approach enables identification of oncogenic and non-oncogenic dependencies of high-risk neuroblastoma and is applicable to other tumor subtypes.

Upon entry into G2 and mitosis (G2/M), dynein dissociates from its interphase cargos and forms mitotic-specific interactions that direct dynein to the nuclear envelope, cell-cortex, kinetochores, and spindle poles to ensure equal segregation of genetic material to the two daughter cells. Although the need for precise regulation of dynein’s activity during mitosis is clear, questions remain about the mechanisms that govern the cell-cycle dependent dynein interactions. Frequently dynein cofactors provide platforms for regulating dynein activity either by directing dynein to specific sites of action or by tuning the motor activity of the dynein motor. In particular the dynein cofactor Nde1 may play a key role in defining dynein’s mitotic activity. During interphase, Nde1 is involved in the dynein-dependent processes of Golgi positioning and minus-end directed lysosome transport (Lam et al., 2009; Yi et al., 2011), but as the cell progresses into G2/M, Nde1 adopts mitotic specific interactions at the nuclear envelope and kinetochores. It is unknown how Nde1’s cell-cycle specific localization is regulated and how, if at all, Nde1 is ultimately able to influence dynein’s recruitment and activity at each of these sites. One candidate is cell-cycle specific phosphorylation of Nde1 by a G2/mitotic specific kinase, cyclinB/Cdk1 (Alkurayaet al. 2011). To study the potential function of the phosphorylation by Cdk1, we assayed the localization of GFP Cdk1Nde1 phospho-mimetic and phospho-mutant constructs at the NE and kinetochores. We demonstrate Cdk1 phosphorylation of Nde1 is required for Nde1 localization to both the NE and to the kinetochore, and also the phosphorylation of Nde1 directly activates physical interactions between Nde1 and its nuclear envelope and the kinetochore-binding partner, CENP-F. Furthermore, physiological studies of Nde1 phosphorylation constructs show that over-expression of GFP Nde1 phospho-mutant causes a significant delay in time from NEBD to anaphase onset, specifically demonstrating a late prometaphase/metaphase arrest. Therefore, we conclude Cdk1 phosphorylation of Nde1 not only regulates its localization to the nuclear envelope and kinetochore but also plays an important functional role in Nde1’s mitotic activity in vivo. In addition to understanding how the cell cycle specific activity of Nde1 is regulated, to fully comprehend how dynein functions during mitosis it is necessary to understand how Nde1 is able to modulate dynein’s activity. Nde1 is typically believed to act as a bridge between dynein and specific cellular cargo by physically interacting both with the cargo and dynein/Lis1 to specify the sites of dynein’s activity. Therefore, to understand how Nde1 functions with Lis1 and dynein during mitosis, we created point mutations in the N-terminal coiled-coil domain that specifically disrupted either the Nde1-Lis1 interaction or the Nde1-dynein interaction. We find that disrupting the Nde1-dynein interaction has more severe phenotypic effects compared to disrupting the Nde1-Lis1 interaction: expression of GFP Nde1 del dynein mutant caused a significant delay in anaphase onset while GFP Nde1 del Lis1 only caused a slight increase in cell cycle duration before anaphase onset. Phenotypic analysis suggests that the effects of abolishing the Nde1-dynein interaction on mitotic progression may be due to defects in maintaining kinetochore-microtubule stability during metaphase. Nde1 plays a role in this dynein-dependent mitotic activity through recruitment of a subfraction of dynein to the kinetochore by Nde1’s coiled-coil domain. While the phenotypic effect of removing the Lis1-Nde1 interaction is less severe than removing the dynein-Nde1 interaction, the interaction between Lis1 and Nde1 plays an important role in Nde1’s mitotic behavior as it is affects Nde1’s localization at the kinetochore, specifically by influencing Nde’1 interaction with its kinetochore recruitment partner, CENP-F. The entirety of this work demonstrates that Nde1 acts as a link between cellular cargo and dynein behavior as phospho-regulation of Nde1 throughout the cell cycle allows Nde1’s to interact with unique mitotic cargoes and influence the recruitment and activity of dynein at the kinetochore.

PRDM16 is a transcriptional co-regulator that is highly expressed in HSCs and required for their maintenance. It is also involved in translocations in acute myeloid leukemia (AML), myelodysplastic syndromes (MDS) and T-cell acute lymphoblastic leukemia. Prdm16 is expressed as both full-length (f Prdm16) and short-length (s-Prdm16) isoforms, the latter lacking an N-terminal PR domain homologous to SET methyltransferase domains. The roles of both isoforms in normal and malignant hematopoiesis are unclear. In chromosomal rearrangements involving PRDM16, the PR domain is deleted. Furthermore, overexpression of s-Prdm16, but not f-Prdm16, can cause leukemia in a p53-/- background predisposed to malignancy. Based on this, s-Prdm16 has been proposed as an oncogene whereas f-Prdm16 has been suggested to possess tumor suppressor activity. The aim of this thesis was to more clearly elucidate the role of each Prdm16 isoform in normal and malignant hematopoiesis. We first showed that Prdm16 is essential for adult HSC maintenance using a conditional deletion mouse model specific for hematopoietic cells, as previous findings using an embryonic-lethal global Prdm16-/- mouse demonstrated this only in fetal liver. We then found, using a specific f-Prdm16-/- mouse model, that full-length Prdm16 is essential for HSC maintenance and induces multiple genes involved in GTPase signaling and represses inflammation. Based on a comparison of Prdm16-/- HSCs lacking both isoforms, and f-Prdm16-/- HSCs which express s-Prdm16, we were able to infer some hematopoietic properties of s-Prdm16 – namely that this isoform induces inflammatory gene expression and supports development of a Lineage-Sca1+cKit- lymphoid progenitor distinct from CLPs which predominantly differentiates into marginal zone B cells. s-Prdm16 expression alone, however, was not sufficient to maintain HSCs. We used a mouse model of human MLL-AF9 leukemia and found that leukemia derived from Prdm16-deficient HSCs had extended latency, although expression of Prdm16 decreases during MLL-AF9 transformation and is undetectable in ex vivo leukemic cells. Forced expression of f-Prdm16 in these cells further extended leukemic latency, while forced expression of s-Prdm16 shortened latency. Gene expression profiling using RNAseq indicated that forced expression of f-Prdm16 resulted in altered respiratory metabolism of MLL-AF9 cells, whereas expression of s-Prdm16 induced a strong inflammatory gene signature, comparable to that seen in HSCs expressing only s-Prdm16. Several inflammatory cytokines and chemokines induced by s-Prdm16 are associated with MDS and with a worse prognosis in human AML. Furthermore, leukemia expressing s-Prdm16 had an elevated number of cells with abnormal nuclei, characteristic of dysplasia. Finally, we performed an analysis of PRDM16 in human AML from the publically-available Cancer Genome Atlas dataset, containing clinical and gene expression data for 179 cases of AML. PRDM16 expression negatively correlated with overall survival, both in the entire dataset and in the NPM1 mutated and MLL¬-rearranged subsets, and s-PRDM16 exhibited a stronger correlation than f-PRDM16. HOX gene expression correlated with PRDM16 expression, suggesting that HOX genes may positively regulate PRDM16 expression in AML. In NPM1-mutant and MLL-rearranged subsets of AML, we also found that high PRDM16 expression correlated with an inflammatory gene signature, thus corroborating our findings in mouse MLL-AF9. Our findings demonstrate distinct roles for Prdm16 isoforms in both normal hematopoiesis and AML, and identify s-Prdm16 as one of the drivers of prognostically-adverse inflammatory gene expression in leukemia.

In this thesis, I focus on studies of the mechanism of inactivation in KcsA. Allosteric coupling between the pH gate and the selectivity filter in the protein is hypothesized to be the cause of inactivation. Allosteric coupling refers to changes at one site of a protein due to perturbations at a remote site. In chapter 3, I measured the potassium affinities at the selectivity filter at neutral and low pH, which corresponds to the closed and open conformation at the pH gate. The results show a three order of magnitude shift in the potassium affinity. This is direct evidence that the pH gate and the selectivity filter are coupled, in support of the activation-coupled inactivation hypothesis. The allosteric coupling factor, defined as the ratio of the affinities, can be used as a benchmark to study other factors in the allosteric process, such as the membrane and specific residues. Because of the potential deleterious effect of the acidic pH on the protein and membrane, we studied a mutant E118A&H25R, in which the pH gate is mutated to be open. Thus we were able to measure the K+ affinity change in the open and closed conformation at the pH gate at neutral pH. The results confirmed that the opening of the pH gate results in an energetic stabilization of the collapsed (K+-unbound) state, and shifts the K+ affinity towards looser binding. In chapter 4, I tested the important role of residue F103 in mediating allosteric coupling, as suggested by electrophysiology and crystallography studies. I mutated this residue and measured the allosteric coupling factor on the mutant. The affinity at low pH is much tighter than wild-type and the coupling factor is significantly reduced. From the spectra, I observe local structural changes on I100 and T74 as a result of F103A mutation, implying the interaction among F103, I100 and T74 to mediate the allosteric coupling. F103 is distant from the pH gate and the selectivity filter; its effect on the coupling and inactivation behaviors confirms that inactivation involves coupling between the pH gate and the selectivity filter. In chapter 5, I developed a method to probe those allosteric participants, such as F103 in KcsA by NMR measurements. I tested this method on KcsA, dissecting KcsA into various functional compartments. Various allosteric participants T75Cg T74Cg I100 were identified. The importance of residue T74 for the coupling was confirmed by electrophysiology and NMR thermodynamics characterization. In chapter 6, we applied SSNMR to probe the structural and magnetic properties of superatom clusters.

Growing tissues are communities of cells that cooperate to form a robust, functional organ. Cooperative behavior is enforced by cell competition, wherein comparisons of fitness lead to selective elimination of cells sensed as relatively less healthy. Elimination of these ‘loser’ cells from Drosophila wing imaginal discs results in cell death induced by deployment of a genetic module consisting of the secreted Toll ligand Spätzle (Spz), several Toll related receptors, and NFkB factors. How signaling by this module is activated and restricted only to competing cells is unknown. Here, we investigate the signaling role of Spz in Myc-induced cell competition. We demonstrate that elimination of wild-type loser cells requires local synthesis and activation of Spz in the wing disc. We identify Spätzle Processing Enzyme (SPE) and Modular Serine Protease (modSP) as upstream mediators of Spz-mediated loser cell elimination, and show that an increase in SPE in ‘winner’ cells is required for Spz to kill loser cells. Finally, we show that Spz requires both Toll and Toll-8 to induce apoptosis of wing disc cells. Our results indicate that during cell competition, Spz-mediated signaling is strictly confined to the imaginal disc, allowing errors in tissue fitness to be corrected without compromising organismal physiology.

This dissertation contains two separate yet interconnected pieces of work, which shed light on the complicated RNA regulatory mechanism. The first part, as the main focus of the thesis, characterizes a large pool of human polyadenylated enhancer RNA under deficient nuclear surveillance conditions, and investigates their metabolism mechanisms. The second part elucidates the dynamic localization mechanism of RBBP6 isoform3, which inhibits pre-mRNA 3’ processing by completing with RBBP6 isoform1. Despite being composed of approximately 3 billion base pairs, only 1 to 2% of the human genome codes for proteins. The non-coding DNA regions can however function as transcription units and generate non-coding RNAs such as enhancer-derived RNAs, or eRNAs, that play crucial roles in gene expression regulation, cell differentiation, development, and diseases. Previous studies have suggested that most eRNAs are transcribed by RNA polymerase II (RNAP II), but not polyadenylated. In Chapter 3, I identify a large fraction of polyadenylated enhancer RNAs under deficient nuclear surveillance conditions via genome-wide analyses, and explore their biogenesis and degradation mechanisms. I find that the Integrator complex plays an important role in polyadenylated eRNA biogenesis, and that their exosome-dependent degradation requires two cofactor complexes containing the RNA helicase Mtr4: the PAXT/PPC complex and the NEXT complex. Additionally, the canonical poly(A) polymerases PAP-α and PAP-γ play a major role in the 3’ end processing of pA+ eRNA. Finally, I show that under deficient nuclear surveillance conditions, pA+ eRNAs accumulate in the cytoplasm and associate with polysomes, suggesting that at least some might have translation potential. I also contributed to the discovery of two novel complexes both containing the RNA helicase Mtr4, which is a master player of the nuclear surveillance system. Mtr4 and ZFC3H1 form the PAXT/PPC complex, which facilitates the turnover of polyadenylated nuclear RNAs, including prematurely terminated RNAs (ptRNAs), upstream antisense RNAs (uaRNAs), and eRNAs (see the paper in Appendix II). Mtr4 also associates with NRDE2 to form a complex, functioning in the DNA damage response pathway (see the paper in Appendix III). These works provide additional insights into the complexity and significance of the RNA helicase Mtr4. In the second part of the thesis, presented in Chapter 4, I studied a polyadenylation factor known as Retinoblastoma-binding protein 6 (RBBP6). RBBP6 was initially identified as a large multidomain protein, interacting with tumor suppressors p53 and Rb. Later, its diverse roles were uncovered in cell cycle progression, apoptosis, nucleic acid metabolism, differentiation, and mRNA processing. RBBP6 protein has four isoforms, among which the shortest isoform, iso3, has only one domain: the DWNN (Domain With No Name) domain. The DWNN domain displays high similarities with ubiquitin, implying its function as a novel ubiquitin-like modifier. However, I show that the DWNN domain is actually not a ubiquitin-like modifier, but is itself ubiquitinated. Moreover, the monoubiquitylation of iso3 can facilitate its localization at chromatin. Additionally, I find that the C-terminal tail of iso3 also plays a role in iso3 chromatin localization, presumably by interacting with other factors of the polyadenylation machinery. Pulldown experiments of iso3 followed by mass spectrometry identified Importin7 as an iso3-interacting factor that assists its cytoplasmic retention. Our results identified novel mechanisms for the dynamic localization of RBBP6 iso3, which shed light on the role of iso3 in mRNA 3’ processing and disease.

Le secteur financier a émergé afin d’apporter une réponse à certaines imperfections microéconomiques, principalement de nature informationnelle. Trois rôles principaux ont été identifiés dans la littérature : la sélection et le suivi des emprunteurs (voir par exemple Grossman et Stiglitz (1980) ou Boot et Thakor (1993)), la création d’un actif insensible à la production d’informations privées, à savoir les dépôts bancaires (Gorton et Pennacchi (1990)), et la fourniture d’une assurance contre les besoins de liquidité en présence d’incertitude sur les préférences quant au moment choisi pour la consommation (Diamond et Dybvig (1984)). Mais, si le secteur financier constitue une réponse à certaines défaillances du marché, il opère en présence de certaines autres imperfections microéconomiques qui peuvent réduire son efficacité. Cette thèse s’attache à étudier plus particulièrement deux d’entre elles : le caractère incomplet des marchés et les problèmes d’aléa moral des gestionnaires des banques. L’existence de ces imperfections implique une externalité dans le fonctionnement du secteur financier qui peut justifier une réglementation. Afin que la régulation puisse permettre de traiter ces inefficacités, il est crucial d’identifier d’abord quelles sont les défaillances de marché responsables de l’inefficacité et à travers quels mécanismes elles influent sur les choix des agents. Cette analyse théorique représente l’objectif principal de cette thèse. / The financial sector has emerged because financial institutions help overcome some microeconomic imperfections, mainly informational. Three main roles have been identified in the literature: the screening and monitoring of borrowers (see for instance Grossman and Stiglitz (1980) or Boot and Thakor (1993)), the creation of an informational-insensitive asset out of their liabilities (Gorton and Pennacchi (1990)), and the provision of an insurance against liquidity needs in the presence of uncertainty on the preferences over the timing of consumption (Diamond and Dybvig (1984)). But, if the financial sector has emerged as an answer to some market failures, it is operating in the presence of some other micro imperfections that can reduce its efficiency. This dissertation focuses on two of them: incomplete markets and moral hazard problems. Their existence implies some externality in the functioning of the financial sector that may justify a regulation. In order for the regulation to overcome those inefficiencies, it is crucial to first identify what are those market failures and through which mechanisms they affect the choices of agents. This theoretical analysis is the main objective of this dissertation.

This thesis examines banking regulation in Nigeria. The thesis has three main objectives; First, to elucidate the role and powers of the Central Bank of Nigeria, (CBN) as the apex regulator for the financial system and within the context of banking failures and crises. Second, to engage in a discourse vis-à-vis the law on banking regulation in Nigeria, with a particular focus on the revocation of banking licenses. Finally, to explore the role of other regulatory bodies which work with the CBN. This thesis provides a historical analysis of banking exchanges from the pre-colonial era to modern times, in order to provide an understanding of how political, local and economic settings as well as theories of regulation have impacted and influenced the development of banking regulation in Nigeria. The thesis concludes that the development of banking regulation has been a consequence of the aforementioned factors. The research examines Nigeria's historical experiences with banking failures, including the banking crisis of 2008. The thesis finds that the Nigerian regulator has adopted a reactionary strategy instead of a proactive and pragmatic approach to the various crises, which is imperative for an effective banking regulatory regime. Given the outcome of this examination, the thesis makes a case for reform. In addition, the study examines the banking consolidation, a recapitalization exercise implemented by the CBN in 2004. This mandated all banks to achieve a set minimum capital base. It examines the legal issues which surfaced, including the revocation of banking licenses by the CBN, arguably in 'bad faith', in order to cogitate the overall potential impact on banking regulation. The research embraces the UK and the US as comparator jurisdictions, so as to distill and critique their responses to the global financial crisis of 2007, against the backdrop of the approach adopted in the Nigerian banking crisis of 2008. It finds that the Nigerian response was the least effective of these jurisdictions and that cogent lessons may be drawn from the comparator jurisdictions. Furthermore, the thesis discusses possible reforms to move forward banking regulation in Nigeria.

The ability to sense and respond to environmental cues is crucial for the survival of all organisms. This response is often manifested by exerting control at different levels of gene expression, i.e. transcription, translation and post translation levels. Global control of protein synthesis is frequently exercised at the initial step of translation initiation and is generally achieved by changes in the phosphorylation state of initiation factors or the regulators that interact with them. The formation of ternary complex (TC) is considered first step of translation initiation and depends on the recycling of inactive eIF2-GDP to active eIF2-GTP form. This nucleotide exchange reaction is catalyzed by the eukaryotic initiation factor-2B (eIF2B). eIF2B is composed of a regulatory sub-complex of alphaβdelta subunits and a catalytic sub-complex of the γε subunits. The guanine nucleotide exchange activity of eIF2B is regulated by phosphorylation of eIF2alpha and additionally in mammalian cells, by direct phosphorylation of eIF2B at multiple sites in ε subunit, where most of the catalytic activity of eIF2B resides. Recent unpublished studies in the Pavitt laboratory identified novel phosphorylation sites by Mass Spectrometry in γ and ε subunits of eIF2B catalytic sub-complex. In order to study the functional significance of these phospho-sites for translation initiation, Site Directed Mutagenesis (SDM) was performed to generate Ser to Ala mutants. All mutations are viable and have no significant growth defect on rich or minimal media; however the significance of these sites in yeast growth became apparent by growing yeast in different stress conditions (e.g. Rapamycin, Torin1, amino acid starvation and 1-butanol). Effects on the phosphorylation pattern at these sites were monitored by using custom generated phospho-specific antibodies. All phosphorylation events appear independent of the eIF2alpha kinase (Gcn2p in yeast). The phosphorylation of ε-S528 depends on the presence of ε-S525. This study finds that addition of rapamycin, Torin1, amino acid starvation and butanol, which each inhibits global translation initiation, alters the phosphorylation pattern at ε-S435, ε-S525 and ε-S528 sites. Linking growth to phosphorylation, it appears that phosphorylation at ε-S435 and ε-S525 is directly proportional to growth. Phosphorylation of ε-S435 is necessary for effect of eIF2alpha-Ser51 phosphorylation on protein synthesis while phosphorylation of ε-S528 seems to be a target of various mechanisms. This study also suggests that eIF2Bε may be a key player of the cell cycle progression and phosphorylation changes can serve as marker for the regulation of eIF2B activity. The kinases responsible for phosphorylation at these sites are not yet known in yeast. Further investigation is required to find the functional significance of alterations in phosphorylation pattern to definitively establish eIF2Bε phosphorylation as a mechanism for regulating eIF2B activity in yeast. Models are presented to account for the results obtained that show how phosphorylation of eIF2Bε at these sites may contribute to the control of protein synthesis.