RESUMO
human umbilical venous endothelial cells. 7E3 binding correlated with alphavbeta3-expression in all cell types. Integrin-mediated cell functions were analysed with adhesion and spreading assays on vitronectin. In human umbilical venous endothelial cells, these functions were mediated by alphavbeta3 and in human iliac arterial smooth muscle cells by alphavbeta5. In human umbilical venous smooth muscle cells, both vitronectin receptors were involved. Abciximab potently inhibited alphavbeta3-mediated cell adhesion and spreading. With tirofiban, no significant inhibition of vascular cell functions was observed. The present data demonstrate that vitronectin-cell interactions in vascular cells are mediated via two distinct integrin-receptors, alphavbeta3 and alphavbeta5. Abciximab, which solely inhibits alphavbeta3-mediated cell functions, may be particularly effective in human endothelium and in beta3-integrin expressing vascular smooth muscle cells.
Assuntos
Anticorpos Monoclonais/farmacologia , Endotélio Vascular/metabolismo , Fibrinolíticos/farmacologia , Fragmentos Fab das Imunoglobulinas/farmacologia , Músculo Liso Vascular/metabolismo , Receptores de Vitronectina/efeitos dos fármacos , Tirosina/análogos & derivados , Abciximab , Adesão Celular/efeitos dos fármacos , Endotélio Vascular/citologia , Endotélio Vascular/efeitos dos fármacos , Citometria de Fluxo , Humanos , Artéria Ilíaca/citologia , Artéria Ilíaca/efeitos dos fármacos , Artéria Ilíaca/metabolismo , Imuno-Histoquímica , Integrinas/biossíntese , Músculo Liso Vascular/citologia , Músculo Liso Vascular/efeitos dos fármacos , Oligopeptídeos/isolamento & purificação , Oligopeptídeos/farmacologia , Receptores de Vitronectina/biossíntese , Receptores de Vitronectina/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Tirofibana , Tirosina/farmacologia , Veias Umbilicais/citologia , Veias Umbilicais/efeitos dos fármacos , Veias Umbilicais/metabolismo , Vitronectina/metabolismoRESUMO
The Ca2+- and phospholipid-dependent protein kinase C from rat brain phosphorylates rabbit muscle phosphofructokinase at the same trypsin-labile site as cyclic AMP-dependent protein kinase. However, protein kinase C also effectively phosphorylates one or more separate sites. Incubation of phosphofructokinase in the presence of protein kinase C, phospholipids, Ca2+, and ATP appears to affect the allosteric properties of phosphofructokinase by shifting the fructose 6-phosphate saturation curve to lower substrate concentrations in a time-dependent manner and decreasing cooperativity of the enzyme.
