Identification of gelsolin, a Ca2+-dependent regulatory protein of actin gel-sol transformation, and its intracellular distribution in a variety of cells and tissues.

Abstract

Antiserum prepared against gelsolin, a major Ca'-dependent regulatory protein of actin gel-sol transformation in rabbit lung macrophages, was used to detect the presence of proteins immunologically related to gelsolin in a variety of cells and tissues. Cell extracts were electrophoresed on polyacrylamide gels, and replicas of the gels on cellulose nitrate paper were stained by an indirect immunohistochemical technique. A single band of crossreactive material which comigrates with macrophage gelsolin is found in at least nine different kinds of cells and tissues derived from rabbits and humans and in four lines of cultured cells from humans and rats . Gelsolin was also identified in human serum and plasma, raising the possibility that it may contribute to the clearance of actin from the circulatory system .Using this antiserum, we demonstrated, by indirect immunofluorescent staining of acetone-fixed macrophages and polymorphonuclear leukocytes, that gelsolin resides in the cortical cytoplasm and that during phagocytosis it is concentrated in pseudopodia engulfing particles to be ingested, an area of the cytoplasm actively engaged in movement . In longitudinal cryostat sections of contracted rabbit skeletal muscle, antigelsolin staining was associated with the

Phosphatidylinositol 4,5‐bisphosphate specifically stimulates PP60c‐src catalyzed phosphorylation of gelsolin and related actin‐binding proteins

“…PIP2 does not act on the tyrosine kinase since the phosphorylation rate of RCMlysozyme by pp60 c_src was not affected by the phospholipid. The specificity of pp60 c~src is nevertheless evidenced by the lack of tyrosine phosphorylation activity on gelsolin by pp56 lck , rendering it as unlikely that gelsolin is a substrate for pp56 lck in T lymphocytes, where both substrate and kinase are present [50,51]. This observation of substrate specificity runs parallel to the statement made by Cheng et al [52] who argued that different tyrosine kinases assayed on different cdc2 peptide substrates displayed strict in vitro substrate specificities.…”

Actin reorganization as the molecular basis for the regulation of apoptosis in gastrointestinal epithelial cells

“…8 Both proteins sever, cap and nucleate actin filaments and similar to villin, gelsolin is expressed in very significant amounts in the intestine where it localizes to the apical surface of enterocytes. 9 In this study we describe a fortuitous observation, that deletion of villin and gelsolin renders villus epithelial cells like the crypt epithelial cells, extremely sensitive to both 'spontaneous' and 'radiation-induced' apoptosis. Our study elucidates a new molecular mechanism of apoptosis in the GI epithelium and identifies the complex connections between the hierarchies to undergo apoptotic cell death along the crypt-villus axis.…”

The Actin-Severing Protein Gelsolin Modulates Calcium Channel and NMDA Receptor Activities and Vulnerability to Excitotoxicity in Hippocampal Neurons

“…An array of proteins that bind actin has been identified (for review, see Hartwig and Kwiatkowski, 1991). One broad class of proteins with F-actin binding and severing activity includes gelsolin (Yin and Stossel, 1979;Yin et al, 1981a), villin (Bretscher and Weber, 1980), and adseverin (Maekawa et al, 1989). Another class of actin-binding proteins that bind actin monomers and exhibit relatively weak actin-severing activity includes actin-depolymerizing factor (Bamburg et al, 1980;Morgan et al, 1993) and cofilin (Yonezawa et al, 1985).…”