Regulation of Ras-related RhoB protein expression during the cell cycle.
The immediate-early gene rhoB codes for a small GTP-binding protein highly homologous to the RhoA protein. While RhoA is known to regulate the assembly of focal adhesions and stress fibers in response to growth factors, the function of RhoB remains unknown. In a first attempt to elucidate its function, we examined the variation of the RhoB protein expression in response to induction of its mRNA. We report here that RhoB is an unstable protein rapidly and transiently induced by growth factors in PC12 and HeLa cells. Moreover, RhoB protein accumulation is periodic through the cell cycle. First detected at the G1/S phase transition, the level of the RhoB protein is maximal during the S phase and declines at the S/G2-M transition. This timing suggests that RhoB plays a role in the G1/S phase transition and/or in the S phase of the cell cycle. We also confirm here a vesicular and perinuclear localization of the endogenous RhoB protein induced by growth factors.
Zalcman
G
G
Unité INSERM 248, Faculté de Médecine Lariboisière/Saint-Louis, Paris, France.
Closson
V
V
Linarès-Cruz
G
G
Lerebours
F
F
Honoré
N
N
Tavitian
A
A
Olofsson
B
B
D002453:Cell Cycle; D002460:Cell Line; D000242:Cyclic AMP / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000032:analysis / Q000378:metabolism*; D006367:HeLa Cells / Q000166:cytology / Q000378:metabolism; D006801:Humans; D008565:Membrane Proteins / Q000032:analysis / Q000378:metabolism*; D009414:Nerve Growth Factors / Q000494:pharmacology; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism; D012313:RNA / Q000378:metabolism; D020743:rhoB GTP-Binding Protein
D008565:Membrane Proteins; D009414:Nerve Growth Factors; D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; D012313:RNA; D000242:Cyclic AMP; D019204:GTP-Binding Proteins; D020743:rhoB GTP-Binding Protein