VACM-1, a cul-5 gene, inhibits cellular growth by a mechanism that involves MAPK and p53 signaling pathways.
Vasopressin-activated Ca2+-mobilizing (VACM)-1 gene product is a 780-amino acid membrane protein that shares sequence homology with cullins, a family of genes involved in the regulation of cell cycle. However, when expressed in vitro, VACM-1 attenuates basal and vasopressin- and forskolin-induced cAMP production. Mutating the PKA-dependent phosphorylation site in the VACM-1 sequence (S730AVACM-1) prevents this inhibitory effect. To further examine the biological role of VACM-1, we studied the effect of VACM-1 and S730AVACM-1 proteins on cellular proliferation and gene expression in Chinese hamster ovary and COS-1 cells. Cellular proliferation of VACM-1-expressing cell lines was significantly lower compared with that of the vector-transfected cells, whereas it was significantly increased in S730AVACM-1-derived cell lines. Furthermore, expression of VACM-1 but not S730AVACM-1 protein retarded cytokinesis and prevented MAPK phosphorylation. Screening with the Human PathwayFinder-1 GEArray system and subsequent Western blot analysis demonstrated that VACM-1 induces p53 mRNA and protein expression. In summary, VACM-1 inhibits cellular growth by a mechanism that involves cAMP, MAPK phosphorylation, and p53 expression.
Van Dort
C
C
Dept. of Biology, Peale Science Center, Hope College, Holland, MI 49422-9000, USA.
Zhao
P
P
Parmelee
K
K
Capps
B
B
Poel
A
A
Listenberger
L
L
Kossoris
J
J
Wasilevich
B
B
Murrey
D
D
Clare
P
P
Burnatowska-Hledin
M
M
D000818:Animals; D015152:Blotting, Northern; D015153:Blotting, Western; D016466:CHO Cells; D019556:COS Cells / Q000166:cytology; D002455:Cell Division / Q000502:physiology; D006224:Cricetinae; D003412:Cricetulus; D044842:Cullin Proteins / Q000502:physiology*; D000242:Cyclic AMP / Q000502:physiology; D005786:Gene Expression Regulation; D007150:Immunohistochemistry; D020928:Mitogen-Activated Protein Kinases / Q000502:physiology*; D009154:Mutation; D010766:Phosphorylation; D015398:Signal Transduction / Q000502:physiology*; D016159:Tumor Suppressor Protein p53 / Q000502:physiology*
D044842:Cullin Proteins; D016159:Tumor Suppressor Protein p53; D000242:Cyclic AMP; D020928:Mitogen-Activated Protein Kinases