Components of the Protein Synthesis and Folding Machinery Are Induced in Vascular Smooth Muscle Cells by Hypertrophic and Hyperplastic Agents

doi:10.1074/jbc.270.36.21404

Components of the Protein Synthesis and Folding Machinery Are Induced in Vascular Smooth Muscle Cells by Hypertrophic and Hyperplastic Agents

IDENTIFICATION BY COMPARATIVE PROTEIN PHENOTYPING AND MICROSEQUENCING (*)

From the Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10021 Cardiovascular Institute and Department of Medicine, Mount Sinai School of Medicine, New York, New York 10029

^§§ To whom correspondence should be addressed:
Box 1269, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York, NY 10029.
Tel.: 212-241-0731; Fax: 212-860-7032.

↵^§ Current address: Microvascular Research Division, Boston University, Boston, MA 02215.

Abstract

Vascular smooth muscle cells (VSMC) are the principal cellular component of the blood vessel wall. Atherosclerosis, hypertension, and angiogenesis are associated with abnormal VSMC growth. Angiotensin II is hypertrophic for cultured adult rat aortic VSMC, whereas platelet-derived growth factor and serum are hyperplastic. To identify changes in specific proteins associated with either hyperplastic or hypertrophic growth, high resolution two-dimensional gel electrophoresis was performed on extracts from quiescent rat aortic VSMC and from VSMC exposed for 24 h to growth factors (10% fetal calf serum, platelet-derived growth factor, or angiotensin II). 12 proteins were up-regulated and 5 down-regulated by treatment with growth factors. Eight of the up-regulated and one of the down-regulated proteins were identified by internal protein microsequencing from electroblotted two-dimensional gels or by co-electrophoresis of purified proteins in two-dimensional gels. Four of the proteins up-regulated by growth factors were identified as mediators of protein folding. These were heat shock proteins, HSP-60 and HSP-70, protein disulfide isomerase, and protein disulfide isomerase isozyme Q-2. Additional proteins were identified as elongation factor EF-1β, a component of the protein synthesis apparatus, and calreticulin, another putative molecular chaperone. Vimentin and actin were also up-regulated, whereas an isoform of myosin heavy chain was down-regulated. Hyperplastic and hypertrophic growth were accompanied by similar changes in protein expression, suggesting that both types of growth require up-regulation of the protein synthesis and folding machinery.

Footnotes

↵^¶ Bristol-Meyers Squibb Established Investigator of the American Heart Association.
↵** Recipients of Career Scientist Awards from the Irma T. Hirschl-Monique Weill-Caulier Charitable Trusts.
↵* The Sequencing Laboratory of Memorial Sloan-Kettering Cancer Center is supported by National Cancer Institute Core Grant 5 P30 CA08748-29. This work was supported in part by National Institutes of Health Grants RO1 HL43302 (to M. B. T.) and RO1 NS29814 (to A. R. M.). The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore by hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
↵¹ The abbreviations used are:

VSMC

vascular smooth muscle cells

Ang

angiotensin II

CS

calf serum

HPLC

high performance liquid chromatography

PDGF

platelet-derived growth factor.
- Received May 17, 1995.
- Revision received July 5, 1995.