Cell cycle regulated expression and phosphorylation of hpttg proto-oncogene product.
We recently isolated a cDNA for hpttg, the human homolog of rat pituitary tumor transforming gene. Now we have analysed the expression of hpttg as a function of cell proliferation. hPTTG protein level is up-regulated in rapidly proliferating cells, is down-regulated in response to serum starvation or cell confluence, and is regulated in a cell cycle-dependent manner, peaking in mitosis. In addition, we show that hPTTG is phosphorylated during mitosis. Immunodepletion and in vitro phosphorylation experiments, together with the use of a specific inhibitor, indicate that Cdc2 is the kinase that phosphorylates hPTTG. These results suggest that hpttg is induced by, and may have a role in, regulatory pathways involved in the control of cell proliferation.
Ramos-Morales
F
F
Departamento de Microbiología, Facultad de Biología, Universidad de Seville, Spain.
Domínguez
A
A
Romero
F
F
Luna
R
R
Multon
M C
MC
Pintor-Toro
J A
JA
Tortolero
M
M
D000595:Amino Acid Sequence; D000818:Animals; D016203:CDC2 Protein Kinase / Q000502:physiology; D019556:COS Cells; D002453:Cell Cycle; D002455:Cell Division; D006367:HeLa Cells; D006801:Humans; D008938:Mitosis; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000378:metabolism*; D015513:Oncogene Proteins / Q000378:metabolism*; D010766:Phosphorylation; D000090063:Proto-Oncogene Mas; D064249:Securin; D018909:src Homology Domains
C000715470:MAS1 protein, human; D009363:Neoplasm Proteins; D015513:Oncogene Proteins; D000090063:Proto-Oncogene Mas; D064249:Securin; D016203:CDC2 Protein Kinase