Sandbox Reserved 324: Difference between revisions
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=Function= | =Function= | ||
The eIF2α subunit is considered to function primarily as a regulatory element of eIF2<ref name="1q8k"/>. The eIF2α is also linked to the binding of Met-tRNAimet and [[1s0u|eIF2γ]]. It was determined as well that in fact eIF2α was need for tight binding of eIF2γ and Met-tRNAimet<ref name="1q8k"/>. The eIF2α is also the target of many kinases which become actived when the cell undergoes certain stresses<ref name="1q8k"/>. These kinases include PKR which is activated by virus infection, the heme regulated inhibitor(HRI) which is activated by iron deficiency, PERK which is activated by increased amounts of unfloded proteins in the ER, and GCN2 which is activated by amino acid starvation<ref name="1q8k"/>. As well, Ser51 has been identified as a phosphorylation site for these kinases<ref name="1q8k"/>. When phosporylation of Ser51 occurs it results in a strong inhibition of translation initiation<ref name="1q8k"/>. This is caused by an increased affinity for [[3jui|eIF2B]], which results in a decreased GDP/GTP exchange rate for eIF2, and therefore a decreased population of activated GTP-bound eIF2<ref name="1q8k"/>. | The eIF2α subunit is considered to function primarily as a regulatory element of eIF2<ref name="1q8k"/>. The eIF2α is also linked to the binding of Met-tRNAimet and [[1s0u|eIF2γ]]. It was determined as well that in fact eIF2α was need for tight binding of eIF2γ and Met-tRNAimet<ref name="1q8k"/>. This is seen by the shortened lengths of beta strands β7 and β8 which allow room for binding of both tRNA and eIF2α<ref name="1q8k"/>. This is supported by genetic and biochemical assays done by Roll-Mecak which showed mutation around the putative adenine binding pocket did not affect the binding of eIF2α but did affect the binding of Met-tRNAimet<ref name="roll">PMID:14688270</ref>. The eIF2α is also the target of many kinases which become actived when the cell undergoes certain stresses<ref name="1q8k"/>. These kinases include PKR which is activated by virus infection, the heme regulated inhibitor(HRI) which is activated by iron deficiency, PERK which is activated by increased amounts of unfloded proteins in the ER, and GCN2 which is activated by amino acid starvation<ref name="1q8k"/>. As well, Ser51 has been identified as a phosphorylation site for these kinases<ref name="1q8k"/>. When phosporylation of Ser51 occurs it results in a strong inhibition of translation initiation<ref name="1q8k"/>. This is caused by an increased affinity for [[3jui|eIF2B]], which results in a decreased GDP/GTP exchange rate for eIF2, and therefore a decreased population of activated GTP-bound eIF2<ref name="1q8k"/>. | ||
=References= | =References= | ||
<references/> | <references/> | ||