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Receptor-mediated activation of heterotrimeric guanine nucleotide-binding proteins (G proteins) results in the dissociation of alpha from beta gamma subunits, thereby allowing both to regulate effectors. Little is known about the regions of effectors required for recognition of G beta gamma. A peptide encoding residues 956 to 982 of adenylyl cyclase 2(More)
Three products of the MAP2 gene are known: MAP2A and MAP2B (Mr approximately 200,000) and MAP2C (Mr 70,000). The structural relationship between these MAPs and the basis for their diversity in size are unknown. Previously, we found that a significant fraction of type II cAMP-dependent protein kinase was associated via its regulatory subunits with MAP2A and(More)
Extracts of human platelets contain a 90,000-Da protein that is retained by DNase I-agarose in the presence of Ca2+. The 90-kDa protein, tightly complexed with platelet actin, can be eluted from DNase I-agarose by ethylene glycol bis(beta-aminoethyl ether)-N, N,N',N'-tetraacetic acid (EGTA). The platelet 90-kDa protein is immunologically related to rabbit(More)
A 130,000 Mr protein was isolated from human platelets by sequential DEAE-Sephacel and Sepharose Cl-4B chromatography. Low shear viscometric measurements showed that the enriched protein after DEAE-Sephacel chromatography inhibited actin polymerization. This effect was somewhat greater in the presence of EGTA than in the presence of calcium. Further(More)
Among subfamilies of G-protein-coupled receptors, agonists initiate several cell signaling events depending on the receptor subtype (R) and the type of G-protein (G) or effector molecule (E) expressed in a particular cell. Determinants of signaling specificity/efficiency may operate at the R-G interface, where events are influenced by cell architecture or(More)
The gamma subunit composition of the major bovine brain Go and Gi proteins (GOA, GOB, GOC, Gi1, and Gi2) was characterized using antibodies against specific gamma isoforms. Each of the purified G protein heterotrimers contained a heterogeneous population of gamma subunits, and the profiles of the gamma subunits found with Gi1, Gi2, and GOA were similar. In(More)
Gbetagamma dimer formation occurs early in the assembly of heterotrimeric G proteins. On nondenaturing (native) gels, in vitro translated, (35)S-labeled Ggamma subunits traveled primarily according to their pI and apparently were not associated with other proteins. In contrast, in vitro translated, (35)S-labeled Gbeta subunits traveled at a high apparent(More)
The Gbeta and Ggamma subunit of the heterotrimeric G proteins form a functional dimer that is stable once assembled in vivo or in vitro. The requirements, mechanism, and specificity of dimer formation are still incompletely understood, but represent important biochemical processes involved in the specificity of cellular signaling through G proteins. Here,(More)
Gelsolin is a 90,000-mol-wt Ca2+-binding, actin-associated protein that can nucleate actin filament growth, sever filaments, and cap barbed filament ends. Brevin is a closely related 92,000-mol-wt plasma protein with similar properties. Gelsolin has been reported to be localized on actin filaments in stress fibers, in cardiac and skeletal muscle I-bands,(More)
Receptor activation of heterotrimeric G proteins dissociates G alpha from the G betagamma complex, allowing both to regulate effectors. Little is known about the effector-interaction regions of G betagamma. We had used molecular modeling to dock a peptide encoding the region of residues 956-982 of adenylyl cyclase (AC) 2 onto Gbeta to identify residues on(More)