VACM-1, a cullin gene family member, regulates cellular signaling.
Vasopressin-activated Ca(2+)-mobilizing (VACM-1) receptor binds arginine vasopressin (AVP) but does not have amino acid sequence homology with the traditional AVP receptors. VACM-1, however, is homologous with a newly discovered cullin family of proteins that has been implicated in the regulation of cell cycle through the ubiquitin-mediated degradation of cyclin-dependent kinase inhibitors. Because cell cycle processes can be regulated by the transmembrane signal transduction systems, the effects of VACM-1 expression on the Ca(2+) and cAMP-dependent signaling pathway were examined in a stable cell line expressing VACM-1 in VACM-1 transfected COS-1 cells and in cells cotransfected with VACM-1 and the adenylyl cyclase-linked V(2) AVP receptor cDNAs. Expression of the VACM-1 gene reduced basal as well as forskolin- and AVP-stimulated cAMP production. In cells cotransfected with VACM-1 and the V(2) receptor, the AVP- and forskolin-induced increases in adenylyl cyclase activity and cAMP production were inhibited. The inhibitory effect of VACM-1 on cAMP production could be reversed by pretreating cells with staurosporin, a protein kinase A (PKA) inhibitor, or by mutating S730A, the PKA-dependent phosphorylation site in the VACM-1 sequence. The protein kinase C specific inhibitor Gö-6983 further enhanced the inhibitory effect of VACM-1 on AVP-stimulated cAMP production. Finally, AVP stimulated D-myo-inositol 1,4, 5-trisphosphate production both in the transiently transfected COS-1 cells and in the stable cell line expressing VACM-1, but not in the control COS-1 and Chinese hamster ovary cells. Our data demonstrate that VACM-1, the first mammalian cullin protein to be characterized, is involved in the regulation of signaling.
Burnatowska-Hledin
M
M
Departments of Biology and Chemistry, Peale Science Center, Hope College, Holland, Michigan 49422-9000, USA. hledin@hope.edu
Zhao
P
P
Capps
B
B
Poel
A
A
Parmelee
K
K
Mungall
C
C
Sharangpani
A
A
Listenberger
L
L
D000067956:Adenylyl Cyclase Inhibitors; D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology; D016466:CHO Cells; D019556:COS Cells; D002118:Calcium / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000235:genetics*; D002468:Cell Physiological Phenomena; D005576:Colforsin / Q000494:pharmacology; D006224:Cricetinae; D044842:Cullin Proteins; D000242:Cyclic AMP / Q000096:biosynthesis; D017868:Cyclic AMP-Dependent Protein Kinases / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015870:Gene Expression; D015544:Inositol 1,4,5-Trisphosphate / Q000096:biosynthesis; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology*; D005810:Multigene Family; D011493:Protein Kinase C / Q000502:physiology; D017483:Receptors, Vasopressin / Q000235:genetics* / Q000378:metabolism / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*
D000067956:Adenylyl Cyclase Inhibitors; D018797:Cell Cycle Proteins; C094547:Cul5 protein, rat; C100318:Cullin 1; D044842:Cullin Proteins; D004791:Enzyme Inhibitors; D008565:Membrane Proteins; D017483:Receptors, Vasopressin; D001127:Arginine Vasopressin; D005576:Colforsin; D015544:Inositol 1,4,5-Trisphosphate; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C; D000262:Adenylyl Cyclases; D002118:Calcium