Phosphorylation of elongation factor 2 by EF-2 kinase affects rate of translation.
A new Ca2+/calmodulin-dependent protein kinase has been recently discovered in mammalian cells. The major substrate of this kinase, a protein of relative molecular mass (Mr) approximately equal to 100,000 (100K), has been identified as elongation factor 2 (EF-2), which participates in protein synthesis. The in vivo activity of the EF-2 kinase depends upon growth factors and other agents affecting the level of Ca2+ and cAMP. Its effect on EF-2 activity, however, remained obscure. This work shows that the phosphorylation of EF-2 by the EF-2 kinase results in a drastic inhibition of polyphenylalanine synthesis in poly(U)-directed translation. Phosphorylated EF-2 is completely inactive in translation and, moreover, inhibits the activity of non-phosphorylated EF-2. Dephosphorylation of EF-2 by phosphatase restores its activity. Hence, the phosphorylation of EF-2 directly affects the elongation stage of translation and thus represents a novel mechanism of translational control.
Ryazanov
A G
AG
Institute of Protein Research, Academy of Sciences of the USSR, Moscow Region.
Shestakova
E A
EA
Natapov
P G
PG
D000818:Animals; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D002474:Cell-Free System; D054736:Elongation Factor 2 Kinase; D005786:Gene Expression Regulation; D066298:In Vitro Techniques; D020652:Peptide Elongation Factor 2; D010445:Peptide Elongation Factors / Q000502:physiology*; D010750:Phosphoproteins / Q000502:physiology; D010766:Phosphorylation; D014176:Protein Biosynthesis; D011494:Protein Kinases / Q000378:metabolism* / Q000502:physiology*; D011817:Rabbits
D020652:Peptide Elongation Factor 2; D010445:Peptide Elongation Factors; D010750:Phosphoproteins; D011494:Protein Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D054736:Elongation Factor 2 Kinase