title: VACM-1/cul5 expression in vascular tissue in vivo is induced by water deprivation and its expression in vitro regulates aquaporin-1 concentrations.
abstract: VACM-1, a cul5 gene product, when overexpressed in vitro, has an antiproliferative effect. In vivo, VACM-1/cul5 is present in tissues involved in the regulation of water balance. Neither proteins targeted for VACM-1/cul5-specific degradation nor factors that may regulate its expression in those tissues have been studied. To identify genes that may be misregulated by VACM-1 cDNA, we performed microarray analysis. Our results indicate that in cos-1 cells transfected with VACM-1 cDNA, mRNA levels for several genes, including AQP1, were decreased when compared to the control group. Our results also indicate that in cos-1 cells transfected with VACM-1 cDNA, endogenous AQP1 protein was decreased about 6-fold when compared to the controls. To test the hypothesis that VACM-1/cul5 may be regulated by conditions that compromise water homeostasis in vivo, we determined if 24 h of water deprivation affects VACM-1/cul5 levels or the effect of VACM-1/cul5 on AQP1. VACM-1 mRNA and protein levels were significantly higher in rat mesenteric arteries, skeletal muscle and the heart ventricle but not in the heart atrium from 24-h water-deprived rats when compared to the controls. Interestingly, 24 h of water deprivation increased modification of VACM-1 by an ubiquitin-like protein, Nedd8, essential for cullin-dependent E3 ligase activity. Although water deprivation did not significantly change AQP1 levels in the mesenteric arteries, AQP1 protein concentrations were inversely correlated with the ratio of the VACM-1 to Nedd8-modified VACM-1. These results suggest that VACM-1/cul5 may regulate endothelial AQP1 concentration both in vivo and in vitro.
authors.affiliation: Department of Biology, Hope College, Holland, MI 49422-9000, USA.
authors.forename: Alyssa E
authors.initials: AE
authors.lastname: Johnson
authors.forename: Isabelle P
authors.initials: IP
authors.lastname: Le
authors.forename: Bradley T
authors.initials: BT
authors.lastname: Andresen
authors.forename: Joseph
authors.initials: J
authors.lastname: Stodola
authors.forename: Gary L
authors.initials: GL
authors.lastname: Dewey
authors.forename: Shirley B
authors.initials: SB
authors.lastname: Dean
authors.forename: James
authors.initials: J
authors.lastname: Resau
authors.forename: Pete
authors.initials: P
authors.lastname: Haak
authors.forename: Travis
authors.initials: T
authors.lastname: Ruch
authors.forename: Ashleigh
authors.initials: A
authors.lastname: Sartor
authors.forename: Inara
authors.initials: I
authors.lastname: Lazdins
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Barney
authors.forename: Maria A
authors.initials: MA
authors.lastname: Burnatowska-Hledin
mesh_terms: D000818:Animals; D051398:Aquaporin 1 / Q000235:genetics / Q000378:metabolism*; D019556:COS Cells; D002522:Chlorocebus aethiops; D044842:Cullin Proteins / Q000032:analysis* / Q000235:genetics* / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation; D008297:Male; D008638:Mesenteric Arteries / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D011817:Rabbits; D051381:Rats; D017207:Rats, Sprague-Dawley; D017483:Receptors, Vasopressin / Q000032:analysis* / Q000235:genetics* / Q000378:metabolism; D014162:Transfection; D014452:Ubiquitins / Q000378:metabolism; D014867:Water / Q000378:metabolism; D014868:Water Deprivation / Q000502:physiology
chemical_list: C094547:Cul5 protein, rat; D044842:Cullin Proteins; D012333:RNA, Messenger; D017483:Receptors, Vasopressin; D014452:Ubiquitins; D014867:Water; D051398:Aquaporin 1