Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA. pallen@calvin.bwh.harvard.edu
Gelsolin is an actin monomer binding and filament severing protein synthesized in plasma and cytoplasmic forms differing by an N-terminal amino acid extension and a disulfide bond between Cys-188 and Cys-201. To determine whether this bond altered gelsolin regulation or function, oxidized and reduced plasma gelsolins were assayed for severing, monomer binding and nucleation activity at a variety of rate-limiting calcium concentrations. The results indicate that the disulfide bond in domain 2 of gelsolin influences the transmission of information from C-terminal regulatory sites to functional sites in the N-terminus.