Open AccessInteraction between the cell‐cycle‐control proteins p34 cdc2 and p9 CKShs2
Author(s) -
AZZI Lyamine,
MEIJER Laurent,
REED Steven I.,
PIDIKITI Ravidernath,
TUNG H. Y. Lim
Publication year - 1992
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1992.tb16557.x
Subject(s) - cyclin dependent kinase 1 , cyclin dependent kinase complex , peptide , biochemistry , kinase , protein kinase a , protein subunit , biology , cyclin dependent kinase , cyclin dependent kinase 3 , binding site , cell cycle , cyclin dependent kinase 2 , chemistry , microbiology and biotechnology , cell , gene
A universal intracellular factor, the ‘M‐phase‐promoting factor’ (MPF), displaying histone H1 kinase activity and constituted of at least two subunits, p34 cdc2 and cyclin B cdc13 , triggers the G 2 →M transition of the cell cycle in all organisms. The yeast p13 suc1 and p18 cks1 subunits and their functionally interchangeable human homologues, p9 CKShs1 and p9 CKShs2 , directly interact with p34 cdc2 and may actually be part of the MPF complex. We have chemically synthesized p9 CKShs2 and several of its peptide domains in order to investigate the binding of p9 CKShs2 and p34 cdc2 . Several arguments support the hypothesis that the N‐terminal half (peptide B) and the C‐terminal half (peptide E) each contain a p34 cdc2 ‐binding site and that these two binding domains cooperate in establishing a stable p9 CKShs2 ‐ p34 cdc2 complex: (a) only the combination of peptides B + E, and not B or E alone, is able to elute the cdc 2 kinase from p9 CKShs1 ‐Sepharose beads; (b) only immobilized peptides B + E, and not immobilized B or E, bind the cdc2 kinase; (c) only the peptides B + E combination, and not B or E alone, can compete with p9 CKShs1 for cdc2 kinase binding; (d) only when supplemented with E or B free peptide does the cdc2 kinase bind to B‐ or E‐Sepharose beads, respectively. No binding occurs in the absence of free peptide. This additivity cannot be attributed to the formation of a B‐E complex mimicking the full‐length p9 CKShs2 . The cyclin B subunit is not required for the formation of the p9 CKShs2 ‐p34 cdc2 complex through these two binding domains. The implications of the existence of two cooperative p34 cdc2 ‐binding domains in p9 CKShs2 on the structure of the active M‐phase‐specific kinase is discussed.