Expression of VACM-1 protein in cultured rat adrenal endothelial cells is linked to the cell cycle.
The vasopressin-activated calcium-mobilizing (VACM-1) protein is a unique arginine vasopressin (AVP) receptor which shares sequence homology with the cullins, genes involved in the regulation of cell cycle transitions. Unlike either cullins or AVP receptors, however, VACM-1 is expressed exclusively in the vascular endothelial cells and in the renal collecting tubule cells. In order to test the hypothesis that the expression of VACM-1 might be correlated with the cell cycle, and to establish an endothelial cell model for the VACM-1 receptor, we examined VACM-1 expression in rat adrenal medulla endothelial cells (RAMEC). Northern and Western blot analyses of mRNA and protein from RAMEC identified presence of 6.4 kb mRNA and a Mr 81 kDa protein, respectively. Immunostaining of RAMEC with anti-VACM-1 antibodies and Western blot analyses indicated that in RAMEC, VACM-1 protein expression is dependent on the cell cycle. VACM-1 protein virtually disappears during the S phase and localizes to the cytosol during cell division and to the cell membrane at the completion of cytokinesis. Furthermore, pretreatment of RAMEC with anti-VACM-1 specific antibodies increased basal levels of Ca2+and attenuated the AVP-dependent increase in cytosolic Ca2+. In summary, these results indicate that VACM-1 protein expression in RAMEC membrane is linked to the cell cycle, and consequently, VACM-1 may be involved in the regulation of cell division.
Burnatowska-Hledin
Department of Biology, Peale Science Center, Hope College, Holland, MI 49422-9000, USA. hledin@hope.edu
Zeneberg
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Roulo
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Grobe
J
J
Zhao
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Lelkes
P I
PI
Clare
P
P
Barney
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C
D000313:Adrenal Medulla / Q000166:cytology / Q000502:physiology*; D000818:Animals; D016590:Aphidicolin / Q000494:pharmacology; D020013:Calcium Signaling / Q000502:physiology; D002453:Cell Cycle / Q000187:drug effects / Q000502:physiology*; D002462:Cell Membrane / Q000502:physiology; D002467:Cell Nucleus / Q000502:physiology; D002478:Cells, Cultured; D044842:Cullin Proteins; D004727:Endothelium / Q000166:cytology / Q000502:physiology; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology*; D007150:Immunohistochemistry; D008565:Membrane Proteins / Q000235:genetics*; D051381:Rats; D017483:Receptors, Vasopressin / Q000235:genetics*; D014158:Transcription, Genetic
C094547:Cul5 protein, rat; D044842:Cullin Proteins; D008565:Membrane Proteins; D017483:Receptors, Vasopressin; D016590:Aphidicolin