Human plasma gelsolin binds to fibronectin.

S E Lind,P A Janmey

doi:10.1016/s0021-9258(18)90687-3

Abstract

Human plasma gelsolin, a 93,000-dalton actin-binding protein binds to human plasma fibronectin. Qualitative data obtained from experiments employing quasi-elastic light scattering, sucrose gradient sedimentation, gel filtration chromatography, and fibronectin polymerization indicate that gelsolin and fibronectin form a complex in solution. Solid-phase binding studies show that both human plasma and rabbit macrophage gelsolin bind to immobilized fibronectin with a Kd of about 1 microM in a 1:1 complex. The ability of gelsolin to interact with actin was not affected by the presence of fibronectin. Fibronectin also increased the amount of gelsolin binding to fibrin clots. Binding of gelsolin to fibronectin may serve to localize plasma gelsolin in regions where fibronectin is deposited, such as inflammatory sites.

Highlights

From the Hemutology-Oncolo,qy Unit, Massachusetts GeneralHospital and the Department of Medicine, Harvard Medical School, Boston, M&sachuset&-02114
The two proteins are synthesized at different rates and the higher-molecular-weight form is secreted, while the Measurement of Gelsolin Binding to Fibronectin and Other Proteins lower-molecular-weight formis retained in the cytoplasm [5]
The unbound tibronectin was removed and the wells washed 5 tipes with PBS containing 0.05% Tween 20.Using radiolabeled FN we found that 0.74r g of fibronectin to determine if gelsolin interacts with FN

Summary

Human Plasma GelsolinBinds to Fibronectin*

A number of investigators have described a 90-95-kDa uents of the reaction mixture by gel filtration on a column of Sephprotein in plasma that shortens actin filaments [1,2,3,4] This protein is closely related, butnot identical to gelsolin, an actin-associated protein of mammalian cytoplasm. The unbound tibronectin was removed and the wells washed 5 tipes with PBS containing 0.05% Tween 20.Using radiolabeled FN we found that 0.74r g of fibronectin to determine if gelsolin interacts with FN. 50 p1 of a solution containing a hances gelsolin incorporation into fibrin clots. Greater than 94% of the labeled gelsolin (110,000cpm) was recovered

Viscosity Measurements

RESULTS

Gelsolin bound

NO ADDED FN

DISCUSSION