Evidence for regulation of protein synthesis at the elongation step by CDK1/cyclin B phosphorylation.
Eukaryotic elongation factor 1 (eEF-1) contains the guanine nucleotide exchange factor eEF-1B that loads the G protein eEF-1A with GTP after each cycle of elongation during protein synthesis. Two features of eEF-1B have not yet been elucidated: (i) the presence of the unique valyl-tRNA synthetase; (ii) the significance of target sites for the cell cycle protein kinase CDK1/cyclin B. The roles of these two features were addressed by elongation measurements in vitro using cell-free extracts. A poly(GUA) template RNA was generated to support both poly(valine) and poly(serine) synthesis and poly(phenylalanine) synthesis was driven by a poly(uridylic acid) template. Elongation rates were in the order phenylalanine > valine > serine. Addition of CDK1/cyclin B decreased the elongation rate for valine whereas the rate for serine and phenylalanine elongation was increased. This effect was correlated with phosphorylation of the eEF-1delta and eEF-1gamma subunits of eEF-1B. Our results demonstrate specific regulation of elongation by CDK1/cyclin B phosphorylation.
Station Biologique de Roscoff, Université Pierre et Marie Curie (UFR 937), Centre National de la Recherche Scientifique (UPR 9042), Institut National des Sciences de l'Univers, BP 74, 29682 Roscoff Cedex, France.
A
A
Monnier
R
R
Bellé
J
J
Morales
P
P
Cormier
S
S
Boulben
O
O
Mulner-Lorillon
D000818:Animals; D016203:CDC2 Protein Kinase / Q000378:metabolism*; D002474:Cell-Free System; D019926:Cyclin B / Q000378:metabolism*; D020648:Peptide Elongation Factor 1 / Q000378:metabolism; D010649:Phenylalanine / Q000378:metabolism; D010766:Phosphorylation; D014176:Protein Biosynthesis; D011506:Proteins / Q000235:genetics; D012313:RNA / Q000235:genetics / Q000378:metabolism; D011817:Rabbits; D012156:Reticulocytes / Q000737:chemistry / Q000378:metabolism; D012694:Serine / Q000378:metabolism; D013698:Templates, Genetic; D013997:Time Factors; D014633:Valine / Q000378:metabolism
D019926:Cyclin B; D020648:Peptide Elongation Factor 1; D011506:Proteins; D012694:Serine; D010649:Phenylalanine; D012313:RNA; D016203:CDC2 Protein Kinase; D014633:Valine