RESUMO
Core facilities play a central role in the life sciences by generating data and ensuring quality standards. Their contributions to research should be appropriately acknowledged or cited in research papers.
Assuntos
Bibliometria , Disciplinas das Ciências Biológicas , PublicaçõesRESUMO
In protein synthesis translation factor eIF2 binds initiator tRNA to ribosomes and facilitates start codon selection. eIF2 GDP/GTP status is regulated by eIF5 (GAP and GDI functions) and eIF2B (GEF and GDF activities), while eIF2α phosphorylation in response to diverse signals is a major point of translational control. Here we characterize a growth suppressor mutation in eIF2ß that prevents eIF5 GDI and alters cellular responses to reduced eIF2B activity, including control of GCN4 translation. By monitoring the binding of fluorescent nucleotides and initiator tRNA to purified eIF2 we show that the eIF2ß mutation does not affect intrinsic eIF2 affinities for these ligands, neither does it interfere with eIF2 binding to 43S pre-initiation complex components. Instead we show that the eIF2ß mutation prevents eIF5 GDI stabilizing nucleotide binding to eIF2, thereby altering the off-rate of GDP from eIF2â¢GDP/eIF5 complexes. This enables cells to grow with reduced eIF2B GEF activity but impairs activation of GCN4 targets in response to amino acid starvation. These findings provide support for the importance of eIF5 GDI activity in vivo and demonstrate that eIF2ß acts in concert with eIF5 to prevent premature release of GDP from eIF2γ and thereby ensure tight control of protein synthesis initiation.
Assuntos
Fator de Iniciação 2B em Eucariotos/metabolismo , Inibidores de Dissociação do Nucleotídeo Guanina/metabolismo , Biossíntese de Proteínas , Proteínas Repressoras/metabolismo , Sequência de Aminoácidos , Sequência Conservada , Fator de Iniciação 2B em Eucariotos/química , Fator de Iniciação 2B em Eucariotos/genética , Evolução Molecular , Inibidores de Dissociação do Nucleotídeo Guanina/química , Guanosina Difosfato/metabolismo , Guanosina Trifosfato/metabolismo , Modelos Moleculares , Mutação , Ligação Proteica , Conformação Proteica , RNA de Transferência/genética , RNA de Transferência/metabolismo , Proteínas Repressoras/química , Leveduras/efeitos dos fármacos , Leveduras/genética , Leveduras/metabolismoRESUMO
OBJECTIVE: To investigate the feasibility and usefulness of an online information and skills development intervention for carers of individuals with anorexia nervosa (AN) and individuals with AN. METHOD: Thirty-seven carers and seventeen individuals with AN were recruited; carers completed the intervention Overcoming Anorexia Online (OAO), with random allocation to receiving additional clinician guidance (OAO-G) or no guidance (OAO-NoG). Level of expressed emotion, distress, depressive symptoms, experience of caregiving, and impact of eating disorder symptoms were assessed in carers and perceptions of changes in their carers' expressed emotion were assessed in individuals with AN. Participants completed questionnaires at pre-intervention, post-intervention and 3-month follow-up. RESULTS: Significant reductions were found for carer intrusiveness, negative experiences of caregiving, and the impact of starvation and guilt. Within group effect sizes suggested mixed findings with respect to whether greater benefits were conferred for carers receiving clinician guidance. Decreases in perceived intrusiveness of the carer by the individual with AN were associated with a large effect size. DISCUSSION: Results demonstrate the feasibility and usefulness of an online intervention for carers. Further examination of the efficacy of the intervention for both carers and individuals with AN is warranted.
