Inhibition of cyclin D-cdk activity in cell cycle arrest of Swiss 3T3 cells by CeReS-18, a novel cell regulatory sialoglycopeptide.
CeReS-18 is a unique negative regulator of cell proliferation with a wide array of target cells. To elucidate the mechanism by which CeReS-18 mediates cell growth inhibition, the possibility that CeReS-18 alters the function of G1 cyclins and their respective cyclin-dependent kinases (cdks) has been examined in mouse fibroblasts (Swiss 3T3) synchronized by CeReS-18. We show here that cyclin D-associated cdk activity is significantly inhibited in the CeReS-18-treated cells. Corresponding to the inhibited cdk function, we demonstrate a low expression of cyclin D in mid G1 determined by Western blot analysis, and cyclin D was greatly reduced in the immunocomplex recovered with antibody to cdk4 and cdk6. Previously, we have shown that the retinoblastoma susceptibility gene product (pRb), a key substrate of cyclin D-cdk complex, was maintained in the hypophosphorylated state in the CeReS-18-inhibited cells. We conclude here that cyclin D/cdk4,6/pRb is the major pathway by which CeReS-18 mediates cell cycle arrest.
Zhao
K
K
Center for Basic Cancer Research, College of Arts and Sciences, Manhattan, Kansas, 66506, USA.
Fattaey
H K
HK
Quinton
T M
TM
Johnson
T C
TC
D016475:3T3 Cells; D000818:Animals; D042846:CDC2-CDC28 Kinases; D002453:Cell Cycle / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D056741:Cyclin D; D051357:Cyclin-Dependent Kinase 2; D051358:Cyclin-Dependent Kinase 4; D051361:Cyclin-Dependent Kinase 6; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors* / Q000096:biosynthesis; D016213:Cyclins / Q000037:antagonists & inhibitors* / Q000096:biosynthesis; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D016193:G1 Phase / Q000187:drug effects; D051379:Mice; D017346:Protein Serine-Threonine Kinases / Q000096:biosynthesis; D011518:Proto-Oncogene Proteins; D012795:Sialoglycoproteins / Q000494:pharmacology*; D013997:Time Factors
C115243:CeReS-18 protein, Bos taurus; D056741:Cyclin D; D016213:Cyclins; D011518:Proto-Oncogene Proteins; D012795:Sialoglycoproteins; D017346:Protein Serine-Threonine Kinases; D042846:CDC2-CDC28 Kinases; C495893:Cdk2 protein, mouse; C495902:Cdk4 protein, mouse; C495912:Cdk6 protein, mouse; D051357:Cyclin-Dependent Kinase 2; D051358:Cyclin-Dependent Kinase 4; D051361:Cyclin-Dependent Kinase 6; D018844:Cyclin-Dependent Kinases