Evidence for Rap1 in vascular smooth muscle cells: Regulation of their expression by platelet-derived growth factor BB

• Published in: FEBS letters Vol. 342; no. 2; pp. 159 - 164
• Main Authors: Quarck, R., Bryckaert, M., Magmer, C., Corvazier, E., Bredoux, R., de Gunzburg, J., Fontenay, M., Tobelem, G., Enouf, J.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 04-04-1994; Elsevier
• Subjects: Animals; Becaplermin; Biological and medical sciences; Cell physiology; Cells, Cultured; DNA - biosynthesis; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation - drug effects; GTP-Binding Proteins - genetics; GTP-Binding Proteins - metabolism; Kinetics; Molecular and cellular biology; Muscle, Smooth, Vascular - drug effects; Muscle, Smooth, Vascular - metabolism; Platelet-derived growth factor; Platelet-Derived Growth Factor - pharmacology; Proto-Oncogene Proteins c-sis; rap GTP-Binding Proteins; Rap1; Rats; Recombinant Proteins - pharmacology; Responses to growth factors, tumor promotors, other factors; RNA, Messenger - genetics; RNA, Messenger - metabolism; Thymidine - metabolism; Vascular smooth muscle cell; HEPES, 4-(2-hydroxyethyl)-1-piperazine ethanesulfonic acid; SERCA, sarco/endoplasmic reticulum Ca 2+ ATPase; SMC, smooth muscle cells; Platelet-derived growth factor; SSC, sodium salt citrate; PKA, cAMP-dependent protein kinase; SDS, sodium dodecyl sulfate; GAP, GTPase activating protein; rap, Ras-proximate; DTT, dithiothreitol; EGTA, [ethylene bis (oxyethylenenitrilo)]tetraacetic acid; PAGE, polyacrylamide gel electrophoresis; Rap1; Vascular smooth muscle cell; C. Sub., catalytic subunit of PKA; MMLV, murine Moloney leukemia virus; RT-PCR, reverse transcription-PCR; PDGF, platelet-derived growth factor; SBTI, soybean trypsin inhibitor; Cell proliferation; GTP; Rat; Rodentia; Smooth muscle; Gene expression; In vitro; Mechanism; Myocyte; Binding protein; Signal transduction; Vertebrata; Mammalia; Polypeptide; Blood vessel; Platelet derived growth factor; Growth factor
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/0014-5793(94)80492-3

The effect of platelet-derived growth factor (PDGF) on Rap1 expression was investigated in rat vascular smooth muscle cells (SMC). First, evidence for Rap1 proteins was shown by their: (i) detection in membranes using a specific anti-Rap1 antibody, (ii) typical shift in electrophoretic mobility as a consequence of reduction, and (iii) cAMP-induced phosphorylation and immunoprecipitation. Then, the mitogenic activity of 10
ng
ml
PDGF AA and BB for 48 h, resulting in a 2- and 5-fold increase in [
3H]thymidine incorporation, was correlated with that of total Rap1 protein expression which was found to be 99% ± 36% and 260% ± 70%, respectively. Further time-course studies established that this up-regulation of Rap1 proteins was only observed after 48 h of PDGF BB treatment. Lastly, comparative RT-PCR of both
rap1a and
rap1b mRNAs showed that PDGF BB also up-regulated the
rap1a mRNA species, which was 1.5-fold increased in contrast with the
rap1b mRNA species. It is concluded that the PDGF BB-induced SMC proliferation is associated with an up-regulation of Rap1a protein.