Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027960 (mole)
 21,279 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Phosphorylation of caldesmon from duck gizzard by Ca-phospholipid-dependent protein kinase was investigated. Ca-phospholipid-dependent protein kinase transfers about 3.5 moles of phosphate per mole of caldesmon (140 kDa). Tropomyosin does not affect, while calmodulin strongly inhibits the phosphorylation of caldesmon by Ca-phospholipid-dependent protein kinase. Data from one-dimensional peptide mapping suggest that the sites phosphorylated by the enzyme are located in fragments with apparent molecular weights of 43 and 35 kDa, which are supposed to be located in the vicinity of N- or C-termini of the protein molecule and involved in the caldesmon interaction with actin and calmodulin.
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PMID:[Localization of segments, phosphorylated by Ca-phospolipid-dependent protein kinase in smooth muscle caldesmon]. 271 86

The thin-filament protein h-caldesmon (the high molecular weight isoform of caldesmon) is phosphorylated in resting and contracted porcine carotid arteries. Phosphorylation of h-caldesmon in intact tissue occurs at sites that are covalently modified by mitogen-activated protein kinase (MAPK) in vitro. In this study, we have evaluated MAPK activation in arteries in response to mechanical load and pharmacological stimulation. MAPK was extracted from resting and stimulated porcine carotid arteries and then partially purified by anion-exchange fast-performance liquid chromatography. MAPK activity was separated into two peaks corresponding to the tyrosine-phosphorylated 42- and 44-kD isoforms of MAPK (p42MAPK and p44MAPK, respectively). Of the total MAPK activity, 42% was associated with p42MAPK, and 58% was associated with p44MAPK, this percentage was not altered by stimulation of the muscles with either KCl (110 mmol/L) or phorbol 12,13-dibutyrate (PDBu, 1 mumol/L). Both p42MAPK and p44MAPK, purified from porcine carotid arteries, phosphorylated h-caldesmon at the same sites and to levels approaching or > 1 mol phosphate per mole protein. In unloaded muscle strips, MAPK activity was 39 pmol.min-1.mg protein-1 when assayed with the peptide substrate APRTPG-GRR. MAPK activity increased in response to incremental mechanical loading to a maximum of 99 pmol.min-1.mg protein-1 at 16 x 10(3) N/m2. MAPK activity could be further increased in loaded muscles by pharmacological stimulation. With KCl stimulation, MAPK activities rose to a peak of 205 pmol.min-1.mg protein-1 at 10 minutes and then declined to basal values at 30 and 60 minutes.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Activation of mitogen-activated protein kinase in porcine carotid arteries. 783 28

Caldesmon interaction with smooth muscle myosin and its ability to cross-link actin filaments to myosin were investigated by the use of several bacterially expressed myosin-binding fragments of caldesmon. We have confirmed the presence of two functionally different myosin-binding sites located in domains 1 and 3/4a of caldesmon. The binding of the C-terminal site is highly sensitive to ionic strength and hardly participates in acto-myosin cross-linking, while the N-terminal binding site is relatively independent of ionic strength and apparently contains two separate myosin contact regions within residues 1-28 and 29-128 of chicken gizzard caldesmon. Both these N-terminal sub-sites are involved in the interaction with myosin and are predominantly responsible for the caldesmon-mediated high-affinity cross-linking of actin and myosin filaments, without affecting the affinity of direct acto-myosin interaction. Binding of caldesmon and its fragments to myosin or rod filaments revealed affinity in the micromolar range. We determined various stoichiometries at maximal binding, which depended on the ionic strength and the concentration of Mg2+ ions. At 30 mM NaCl and 1 mM Mg2+ the maximum stoichiometry was 4 moles of caldesmon (or caldesmon fragment) per mole of myosin. At 130 mM NaCl/1 mM Mg2+, or at 30 mM NaCl/5mM Mg2+ it decreased to about two caldesmon molecules bound per myosin, while remaining 4:1 for individual caldesmon fragments, suggesting that all binding sequences on myosin were still fully capable of interaction. A further increase in the Mg2+ concentration led to a substantial decrease in both the affinity and maximum stoichiometry of caldesmon and the fragments binding to myosin. We suggest that caldesmon-myosin interaction varies according to the conformation of caldesmon in solution, that caldesmon-binding sites on myosin are not well defined and that their accessibility is determined by spatial organization and is blocked by divalent cations like Mg2+.
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PMID:Location and functional characterization of myosin contact sites in smooth muscle caldesmon. 935 55

Smooth muscle hamartoma (SMH) is a rare benign congenital or acquired lesion sometimes associated with Becker's nevus (Becker's melanosis). We report an unusual lesion with combined features of SMH and melanocytic nevus. The patient is a 49-year-old male with a history of a changing 'mole' on the left upper back. Clinical examination showed a solitary 1.2-cm nodule with central gray pigmentation. Histological examination showed a relatively well-circumscribed intradermal lesion. The superficial portion of the lesion consisted of melanocytes with nevoid morphology. The melanocytes had congenital pattern of distribution. Lesional melanocytes acquired a spindled morphology in the deeper dermis. The base of the lesion consisted of intersecting smooth muscle fascicles focally admixed with spindled melanocytes. The melanocytic component strongly expressed melanoma antigen recognized by T-cells-1 (MART-1) and HMB-45. The smooth muscle component was strongly positive for smooth muscle actin and h-caldesmon. Neither components showed significant cytological atypia or mitotic activity. Unlike a recently reported case of SMH combined with a melanocytic nevus and basal cell carcinoma, the current lesion did not occur in association with a Becker's nevus.
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PMID:Smooth muscle hamartoma associated with a congenital pattern melanocytic nevus, a case report and review of the literature. 1854 54

Tumors that originate from neural crest-derived cells represent a heterogeneous group of neoplasms including benign and malignant tumors with melanocytic and schwannian differentiation. The immunophenotype of these tumors is well known but little is known about the expression of smooth muscle/myofibroblastic markers in these tumors. A total of 590 neural crest-derived tumors (50 benign schwannomas, five malignant peripheral nerve sheath tumors, 80 neurofibromas, 240 nevocytic nevi, 115 primary melanomas, and 100 melanoma metastases) were studied with respect to alpha-smooth muscle actin and muscle-specific actin expression. alpha-Smooth muscle actin and muscle-specific actin-positive tumor cells with a co-expression of S-100 protein were found in one benign schwannoma, one primary cutaneous melanoma, and four melanoma metastases. Four of these cases were examined ultrastructurally, but typical actin filaments with focal densities were not found in any of the four. Other immunohistochemical markers examined including desmin, h-caldesmon and smooth muscle myosin heavy chain were negative in the tumor cells. The present results suggest that neural crest-derived tumors could show expression of alpha-smooth muscle actin on rare occasion.
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PMID:Actin expression in neural crest cell-derived tumors including schwannomas, malignant peripheral nerve sheath tumors, neurofibromas and melanocytic tumors. 1915 61