Learn More
The beta-thymosins are a family of highly polar peptides which serve in vivo to maintain a reservoir of unpolymerized actin monomers. In vitro, beta-thymosins form 1:1 complexes with actin monomers and inhibit both polymerization and exchange of the bound nucleotide. Circular dichroism data indicate that free thymosin beta 4 is predominantly unstructured,(More)
The complete amino-acid sequence of actin of rabbit skeletal muscle was determined. The actin polypeptide chain is composed of 374 residues, including one residue of the unusual amino acid N(r)-methyl histidine, and has a calculated molecular weight of 41,785. The sequence of actin was determined by isolating the peptides produced by cleavage of the protein(More)
At relatively high concentrations of myosin light chain kinase, a second site on the 20,000-dalton light chain of smooth muscle myosin is phosphorylated (Ikebe, M., and Hartshorne, D. J. (1985) J. Biol. Chem. 260, 10027-10031). In this communication the site is identified and kinetics associated with its phosphorylation and dephosphorylation are described.(More)
Smooth muscle heavy meromyosin (HMM) is phosphorylated by the Ca2+-activated phospholipid-dependent protein kinase, i.e. protein kinase C, at three sites on each 20,000-dalton light chain. Phosphorylation of three sites also is observed with isolated 20,000-dalton light chain and HMM subfragment 1. The phosphorylation sites are serine 1, serine 2, and(More)
The distribution of nonmuscle myosin isoforms in brain and aorta was studied by using polyclonal antibodies against two synthetic peptides selected from a region near the carboxyl terminus of bovine brain (peptide IIB) and human macrophage (peptide IIA) myosin. Immunoblots of brain homogenates and purified myosin showed two major bands stained by(More)
The minibrain kinase (Mnbk)/dual specificity Yak 1-related kinase 1A (Dyrk1A) gene is implicated in the mental retardation associated with Down's syndrome. It encodes a proline-directed serine/threonine kinase whose function has yet to be defined. We have used a solid-phase Mnbk/Dyrk1A kinase assay to aid in the search for the cellular Mnbk/Dyrk1A(More)
During the course of the expression of a 47-kDa COOH-terminal fragment of brain-type nonmuscle myosin heavy chain (MIIBF47), we found two closely related forms of MIIB, designated MIIB alpha and MIIB beta, in rabbit brains. The B alpha form corresponded to SMemb, described by Kuro-o et al. [(1991) J. Biol. Chem. 266, 3768] and was the more abundant form in(More)
Actin is the principal constituent of the thin filaments of muscle, and in order to provide information basic to understanding the molecular basis of actin function we have studied its amino acid sequence. The isolation, compositions, and sequences of cyanogen bromide peptides, ranging in size from 3 to 44 residues, have previously been reported (ELZINGA,(More)
Antisera were produced against two synthetic peptides having sequences specific for cellular myosin heavy chains from human macrophages (peptide IIA) and bovine brain (peptide IIB). Immunoblots of tissue extracts were made with these antibodies, and they showed that mammalian cells have at least three distinct cellular myosin heavy chain isoforms. Two of(More)
Lysine 372 of N-ethylmaleimide actin was specifically (60%) labeled by 7-chloro-4-nitrobenzeno-2-oxa-1,3-diazole chloride (NBD-Cl), which also reacted with lysines on cyanogen bromide fragment 17 (20%) and other undetermined residues (20%). Isolation of N-ethylmaleimide peptides and two-dimensional peptide mapping demonstrated that 90% of bound(More)