Identification of a restriction point at the M/G1 transition in CHO cells.
The regulation of cell cycle progression in normal mammalian cells is dependent on the presence of growth factors. In their absence, non-transformed cells will stop dividing and enter the quiescent state (G0). We show here that in Chinese hamster ovary cells, at least two serum-dependent points exist during G1 that lead to different cellular responses. The first point is located immediately after mitosis and is suggested to link with apoptosis. The second point is located late in G1, and probably corresponds with the 'classic' restriction point R. Cells depleted of serum after the first restriction point will not stop randomly in G1 but continue G1 progression until they reach the late restriction point, as marked by translocation of p42(MAPkinase) (ERK2) to the nucleus.
E
Hulleman
Department of Molecular Cell Biology, Utrecht University, Padualaan 8, 3584, Utrecht, The Netherlands.|Department of Experimental Oncology, European Institute of Oncology, via Ripamonti 435, 20141, Milan, Italy.
E
E
Hullemann
Department of Molecular Cell Biology, Utrecht University, Padualaan 8, 3584, Utrecht, The Netherlands.
J J M
JJM
Bijvelt
Department of Molecular Cell Biology, Utrecht University, Padualaan 8, 3584, Utrecht, The Netherlands.
A J
AJ
Verkleij
Department of Molecular Cell Biology, Utrecht University, Padualaan 8, 3584, Utrecht, The Netherlands.
C T
CT
Verrips
Department of Molecular Cell Biology, Utrecht University, Padualaan 8, 3584, Utrecht, The Netherlands. j.boonstra@bio.uu.nl.
J
J
Boonstra
D000818:Animals; D017209:Apoptosis / Q000502:physiology; D016466:CHO Cells; D006224:Cricetinae; D016193:G1 Phase / Q000502:physiology*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D008938:Mitosis / Q000502:physiology*; D010766:Phosphorylation; D044967:Serum / Q000502:physiology
D020928:Mitogen-Activated Protein Kinases