FUNCTION: FUNCTIONS IN THE EARLY STEPS OF PROTEIN SYNTHESIS BY FORMING A TERNARY COMPLEX WITH GTP AND INITIATOR TRNA. THIS COMPLEX BINDS TO A 40S RIBOSOMAL SUBUNIT, FOLLOWED BY MRNA BINDING TO FORM A 43S PREINITIATION COMPLEX. JUNCTION OF THE 60S RIBOSOMAL SUBUNIT TO FORM THE 80S INITIATION COMPLEX IS PRECEDED BY HYDROLYSIS OF THE GTP BOUND TO EIF-2 AND RELEASE OF AN EIF-2-GDP BINARY COMPLEX. IN ORDER FOR EIF-2 TO RECYCLE AND CATALYZE ANOTHER ROUND OF INITIATION, THE GDP BOUND TO EIF-2 MUST EXCHANGE WITH GTP BY WAY OF A REACTION CATALYZED BY EIF-2B. * SUBUNIT: HETEROTRIMER COMPOSED OF AN ALPHA, A BETA, AND A GAMMA CHAIN. * PTM: SUBSTRATE FOR AT LEAST 4 KINASES: EIF2AK3/PERK, GCN2, HRI AND PKR. PHOSPHORYLATION STABILIZES THE EIF-2/GDP/EIF-2B COMPLEX AND PREVENTS GDP/GTP EXCHANGE REACTION, THUS IMPAIRING THE RECYCLING OF EIF-2 BETWEEN SUCCESSIVE ROUNDS OF INITIATION AND LEADING TO GLOBAL INHIBITION OF TRANSLATION. * SIMILARITY: BELONGS TO THE EIF-2-ALPHA FAMILY. * SIMILARITY: CONTAINS 1 S1 MOTIF DOMAIN. |
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16-JAN-03
Last Update 13-Mar-03