title: Expression of plasma membrane calcium ATPases in phenotypically distinct canine vascular smooth muscle cells.
abstract: Our laboratory has identified at least two types of vascular smooth muscle cells (VSMCs) that exist in canine arteries and veins: type 1 cells, located in the media express muscle specific proteins but do not proliferate in culture; and type 2 cells, located in both media and adventitia, do not express muscle specific protein but proliferate in culture. Plasma membrane Ca(2+)-ATPases (PMCAs) have been implicated in proliferation control. The present study examines the expression of PMCA isoforms and calmodulin-binding domain splice variants in these two types of canine VSMCs. PMCA protein was found in both type 1 and type 2 cells. Reverse transcriptase-polymerase chain reaction assays were developed for canine PMCA calmodulin-binding domain splice variants. We cloned and sequenced isolates corresponding to PMCA1b, 4a and 4b from canine VSMCs. PMCA 2 and 3 were not detected. Freshly isolated type 1 cells expressed PMCA 1b, 4a and 4b, while freshly isolated type 2 cells expressed PMCA1b and 4b. Upon placement in culture, type 2 cells originating from either carotid artery or saphenous vein demonstrated a time-dependent upregulation of PMCA4a mRNA. Treatment with the phosphoinositide 3-kinase inhibitor wortmannin produced concentration-dependent inhibition of both PMCA4a upregulation and [(3)H]thymidine incorporation. These findings suggest a role for phosphoinositide 3-kinase in regulating PMCA expression, which may be important in the control of Ca(2+)-sensitive VSMC functions.
authors.affiliation: Department of Medicine (Cardiovascular Sciences), Baylor College of Medicine, Houston, Texas, 77030, USA. joela@bcm.tmc.edu
authors.forename: J
authors.initials: J
authors.lastname: Abramowitz
authors.forename: A
authors.initials: A
authors.lastname: Aydemir-Koksoy
authors.forename: T
authors.initials: T
authors.lastname: Helgason
authors.forename: S
authors.initials: S
authors.lastname: Jemelka
authors.forename: T
authors.initials: T
authors.lastname: Odebunmi
authors.forename: C L
authors.initials: CL
authors.lastname: Seidel
authors.forename: J C
authors.initials: JC
authors.lastname: Allen
mesh_terms: D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D001483:Base Sequence; D000252:Calcium-Transporting ATPases / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D002339:Carotid Arteries / Q000166:cytology / Q000201:enzymology*; D027682:Cation Transport Proteins; D002462:Cell Membrane / Q000201:enzymology; D002478:Cells, Cultured; D017931:DNA Primers; D018076:DNA, Complementary; D004285:Dogs; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D015870:Gene Expression; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000201:enzymology*; D010641:Phenotype; D053499:Plasma Membrane Calcium-Transporting ATPases; D012333:RNA, Messenger; D012501:Saphenous Vein / Q000166:cytology / Q000201:enzymology*; D017386:Sequence Homology, Amino Acid; D000077191:Wortmannin
chemical_list: D000730:Androstadienes; D027682:Cation Transport Proteins; D017931:DNA Primers; D018076:DNA, Complementary; D004791:Enzyme Inhibitors; D012333:RNA, Messenger; D053499:Plasma Membrane Calcium-Transporting ATPases; D000252:Calcium-Transporting ATPases; D000077191:Wortmannin