The Interaction of Fibulin-1 with Fibrinogen A POTENTIAL ROLE IN HEMOSTASIS AND THROMBOSIS

摘要: The fibulins are an emerging family of extracellular matrix and blood proteins presently having two members designated fibulin-1 −2. Fibulin-1 is the predominant fibulin in blood, present at a concentration 30-40 μg/ml (~1000-fold higher than fibulin-2). During course isolating from plasma by immunoaffinity chromatography, 340-kDa polypeptide was consistently found to co-purify. This protein identified as fibrinogen (Fg) based on its electrophoretic behavior reactivity with Fg monoclonal antibodies. Radioiodinated shown bind transferred onto nitrocellulose filters after SDS-polyacrylamide gel electrophoresis. In enzyme-linked immunosorbent assay, bound (and fibrin) adsorbed microtiter well plastic, conversely, fibulin-1-coated wells. binding also observed surface plasmon resonance assays, dissociation constant (Kd) 2.9 ± 1.6 μM derived. addition, fluorescence anisotropy experiments demonstrated that interaction able occur fluid phase, which suggests complexes could exist blood. To localize portion responsible for interacting fibulin-1, proteolytic fragments were evaluated their ability promote binding. Fragments containing carboxyl-terminal region Bβ chain (residues 216-468) fibulin-1. it incorporate into fibrin clots formed vitro immunologically detected within newly fibrin-containing thrombi associated human atherectomy specimens. between highlights potential new roles hemostasis thrombosis.