title: Characteristics of smooth muscle cell lipoprotein binding proteins (p105/p130) as T-cadherin and regulation by positive and negative growth regulators.
abstract: Smooth muscle cells (SMC) express atypical surface low density lipoprotein (LDL) binding proteins of M(r)105 and M(r)130 (p105 and p130) which have been putatively identified as the cell adhesion glycoprotein T-cadherin. Using cultured human and rat aortic SMC and analysis by ligand (LDL)- and immuno-blotting techniques we now confirm identity of p105 and p130 as T-cadherin, as adjudged by sensitivity to PI-PLC cleavage, insensitivity to trypsin degradation in the presence of calcium, and immunoreactivity to anti-T-cadherin peptide antisera. The function of T-cadherin (p105/p130) in the vasculature is unknown. The proteins were downmodulated by the peptide growth factors PDGF-BB, IGF, EGF, and bFGF, but not by vasoactive peptide hormones (angiotensin II, vasopressin, bradykinin, and endothelin). TGF beta, a recognized inhibitor of SMC proliferation, per se had no effect but inhibited growth factor-induced p105/p130 downmodulation. Expression of p105/p130 in quiescent SMC and growth-stimulated SMC (respectively, in serum-free and serum or PDGF-BB containing culture conditions) was increased by forskolin and 8-Br-cyclic GMP, both anti-mitogenic substances, but was unaffected by phorbol ester, calcium ionophores, or calcium antagonists. The findings are compatible with a function for the lipoprotein binding proteins (T-cadherin) in negative regulation of SMC growth.
authors.affiliation: Department of Research, Basel University Hospital, Switzerland.
authors.forename: Y S
authors.initials: YS
authors.lastname: Kuzmenko
authors.forename: D
authors.initials: D
authors.lastname: Stambolsky
authors.forename: F
authors.initials: F
authors.lastname: Kern
authors.forename: V N
authors.initials: VN
authors.lastname: Bochkov
authors.forename: V A
authors.initials: VA
authors.lastname: Tkachuk
authors.forename: T J
authors.initials: TJ
authors.lastname: Resink
mesh_terms: D000818:Animals; D015820:Cadherins / Q000302:isolation & purification / Q000378:metabolism*; D002352:Carrier Proteins / Q000302:isolation & purification / Q000378:metabolism*; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D006131:Growth Inhibitors / Q000494:pharmacology; D006133:Growth Substances / Q000494:pharmacology; D006801:Humans; D008077:Lipoproteins, LDL / Q000378:metabolism*; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D051381:Rats; D016212:Transforming Growth Factor beta / Q000494:pharmacology
chemical_list: D015820:Cadherins; D002352:Carrier Proteins; D006131:Growth Inhibitors; D006133:Growth Substances; C099972:H-cadherin; D008077:Lipoproteins, LDL; D010982:Platelet-Derived Growth Factor; D016212:Transforming Growth Factor beta