Expression of plasma membrane calcium ATPases in phenotypically distinct canine vascular smooth muscle cells.
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.
Abramowitz
J
J
Department of Medicine (Cardiovascular Sciences), Baylor College of Medicine, Houston, Texas, 77030, USA. joela@bcm.tmc.edu
Aydemir-Koksoy
A
A
Helgason
T
T
Jemelka
S
S
Odebunmi
T
T
Seidel
C L
CL
Allen
J C
JC
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
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