Salt-induced conformational changes in skeletal myosin light chains, troponin-C, and parvalbumin

Biochemistry ◽  
1979 ◽  
Vol 18 (26) ◽  
pp. 5960-5965 ◽  
Author(s):  
Ana Mrakovcic ◽  
Steven Oda ◽  
Emil Reisler
Keyword(s):  
Conformational Changes ◽  
Troponin C ◽  
Light Chains ◽  
Myosin Light Chains ◽  
Skeletal Myosin

scholarly journals DC3, the 21-kDa Subunit of the Outer Dynein Arm-Docking Complex (ODA-DC), Is a Novel EF-Hand Protein Important for Assembly of Both the Outer Arm and the ODA-DC

2003 ◽  
Vol 14 (9) ◽  
pp. 3650-3663 ◽  
Author(s):  
Diane M. Casey ◽  
Kazuo Inaba ◽  
Gregory J. Pazour ◽  
Saeko Takada ◽  
Ken-ichi Wakabayashi ◽  
...  
Keyword(s):  
Troponin C ◽  
Light Chains ◽  
Myosin Light Chains ◽  
Cdna Clones ◽  
Wild Type ◽  
Ef Hand ◽  
Dynein Arms ◽  
Ef Hands ◽  
Flagellar Axoneme ◽  
Chlamydomonas Mutants

The outer dynein arm-docking complex (ODA-DC) is a microtubule-associated structure that targets the outer dynein arm to its binding site on the flagellar axoneme ( Takada et al. 2002 . Mol. Biol. Cell 13, 1015–1029). The ODA-DC of Chlamydomonas contains three proteins, referred to as DC1, DC2, and DC3. We here report the isolation and sequencing of genomic and full-length cDNA clones encoding DC3. The sequence predicts a 21,341 Da protein with four EF-hands that is a member of the CTER (calmodulin, troponin C, essential and regulatory myosin light chains) group and is most closely related to a predicted protein from Plasmodium. The DC3 gene, termed ODA14, is intronless. Chlamydomonas mutants that lack DC3 exhibit slow, jerky swimming because of loss of some but not all outer dynein arms. Some outer doublet microtubules without arms had a “partial” docking complex, indicating that DC1 and DC2 can assemble in the absence of DC3. In contrast, DC3 cannot assemble in the absence of DC1 or DC2. Transformation of a DC3-deletion strain with the wild-type DC3 gene rescued both the motility phenotype and the structural defect, whereas a mutated DC3 gene was incompetent to rescue. The results indicate that DC3 is important for both outer arm and ODA-DC assembly.

scholarly journals Synthesis of rat myosin light chains in heterokaryons formed between undifferentiated rat myoblasts and chick skeletal myocytes.

1981 ◽  
Vol 91 (1) ◽  
pp. 11-16 ◽  
Author(s):  
W E Wright
Keyword(s):  
Primary Cultures ◽  
Muscle Cells ◽  
Thigh Muscle ◽  
Light Chains ◽  
Myosin Light Chains ◽  
Control Of Gene Expression ◽  
Cell Functions ◽  
Cell Extracts ◽  
Skeletal Myosin ◽  
Species Specific

The control of gene expression during terminal myogenesis was explored in heterokaryons between differentiated and undifferentiated myogenic cells by analyzing the formation of species specific myosin light chains of chick and rat skeletal muscle. Dividing L6 rat myoblasts served as the biochemically undifferentiated parent. The differentiated parental cells were mononucleated muscle cells (myocytes) that were obtained from primary cultures of embryonic chick thigh muscle by blocking myotube formation with EGTA and later incubating the postimitotic cells in cytochalasin B. Heterokaryons were isolated by the selective rescue of fusion products between cells previously treated with lethal doses of different cell poisons. 95-99% pure populations of heterokaryons formed between undifferentiated rat myoblasts and differentiated chick myocytes were obtained. The cells were labeled with [35S]methionine, and whole cell extracts were analyzed on two-dimensional polyacrylamide gels. These heterokaryons synthesize the light chain of chick myosin and both embryonic and adult light chains of rat skeletal myosin. Control homokaryons formed by fusing undifferentiated cells to themselves did not synthesize skeletal myosin light chains. Control heterokaryons formed between undifferentiated rat myoblasts and chick fibroblasts also failed to synthesize myosin light chains. These results indicate that differentiated chick muscle cells provide some factor that induces L6 myoblasts to synthesize rat myosin light chains. This system provides a model for investigating the processes by which differentiated cell functions are induced.

scholarly journals Hybrid myosin light chains containing a calcium-specific site from troponin C

1992 ◽  
Vol 204 (1) ◽  
pp. 85-91 ◽  
Author(s):  
Ana Claudia Rasera SILVA ◽  
John KENDRICK-JONES ◽  
Fernando C. REINACH
Keyword(s):  
Troponin C ◽  
Specific Site ◽  
Light Chains ◽  
Myosin Light Chains

scholarly journals Induction of muscle genes in neural cells.

1984 ◽  
Vol 98 (2) ◽  
pp. 427-435 ◽  
Author(s):  
W E Wright
Keyword(s):  
Cell Lines ◽  
Neural Cell ◽  
Light Chains ◽  
Myosin Light Chains ◽  
Neural Cells ◽  
Cell Hybrids ◽  
Skeletal Myosin ◽  
Muscle Genes ◽  
Inducing Factors ◽  
Neural Cell Lines

The regulation of skeletal muscle genes was examined in heterokaryons formed by fusing differentiated chick skeletal myocytes to four different rat neural cell lines. Highly enriched populations of heterokaryons isolated using irreversible biochemical inhibitors were labeled with [35S]methionine and analyzed on two-dimensional gels. Rat skeletal myosin light chains were induced in three of the four cell combinations. The one exception, the S-20 cholinergic cell line, not only failed to synthesize rat muscle proteins but also suppressed chick myogenic functions. Experiments with heterokaryons between chick myocytes and cells from whole embryonic rat brain cultures demonstrated that rat skeletal myosin light chains are inducible in normal diploid neural cells as well as in established neural cell lines. In contrast, dividing cell hybrids between rat myoblasts and rat glial cells were nonmyogenic. These results demonstrate that although neural cells may contain factors that prevent the decision to differentiate along myogenic lines in cell hybrids, most neural cell lines do not dominantly suppress the expression of muscle structural genes in heterokaryons. Furthermore, the skeletal myosin light chain genes in most neural cell lines are regulated by a mechanism that permits them to respond to putative chick skeletal myocyte-inducing factors. The "open" state of these myogenic genes may explain many of the reports of apparent "transdifferentiation" to muscle in neural cultures and neural tumors.

Dictyostelium discoideum myosin: isolation and characterization of cDNAs encoding the regulatory light chain

1989 ◽  
Vol 9 (7) ◽  
pp. 3073-3080
Author(s):  
S R Tafuri ◽  
A M Rushforth ◽  
E R Kuczmarski ◽  
R L Chisholm
Keyword(s):  
Amino Acid ◽  
Light Chain ◽  
Base Pair ◽  
Calcium Binding ◽  
Expression Patterns ◽  
Light Chains ◽  
Myosin Light Chains ◽  
Base Pairs ◽  
Isolation And Characterization ◽  
Skeletal Myosin

Phosphorylation of the regulatory light chains (RMLC) of nonmuscle myosin can increase the actin-activated ATPase activity and filament formation. Little is known about these regulatory mechanisms and how the RMLC are involved in ATP hydrolysis. To better characterize the nonmuscle RMLC, we isolated cDNAs encoding the Dictyostelium RMLC. Using an antibody specific for the RMLC, we screened a lambda gt11 expression library and obtained a 200-base-pair clone that encoded a portion of the RMLC. The remainder of the sequence was obtained from two clones identified by DNA hybridization, using the 200-base-pair cDNA. The composite RMLC cDNA was 645 nucleotides long. It contained 60 base pairs of 5' untranslated, 483 bases of coding, and 102 base pairs of 3' untranslated sequence. The amino acid sequence predicted an 18,300-dalton protein that shares 42% amino acid identity with Dictyostelium calmodulin and 30% identity with the chicken skeletal myosin RMLC. This sequence contained three regions that were similar to the E-F hand calcium-binding domains found in calmodulin, troponin C, and other myosin light chains. A sequence similar to the phosphorylation sequence found in chicken gizzard and skeletal myosin light chains was found at the amino terminus. Genomic Southern blot analysis suggested that the Dictyostelium genome contains a single gene encoding the RMLC. Analysis of RMLC expression patterns during Dictyostelium development indicated that accumulation of this mRNA increases just before aggregation and again during culmination. This pattern is similar to that obtained for the Dictyostelium essential myosin light chain and suggests that expression of the two light chains is coordinated during development.

scholarly journals Sequential disassembly of myofibrils induced by myristate acetate in cultured myotubes.

1987 ◽  
Vol 105 (3) ◽  
pp. 1365-1376 ◽  
Author(s):  
Z X Lin ◽  
J R Eshelman ◽  
S Forry-Schaudies ◽  
S Duran ◽  
J L Lessard ◽  
...  
Keyword(s):  
Troponin C ◽  
Stress Fibers ◽  
Light Chains ◽  
Myosin Light Chains ◽  
Muscle Actin ◽  
Myristate Acetate ◽  
Thin Filaments ◽  
Thick Filaments ◽  
Cultured Myotubes ◽  
Alpha Actin

The phorbol ester TPA induces the sequential disassembly of myofibrils. First the alpha-actin thin filaments are disrupted and then, hours later, the myosin heavy chain (MHC) thick filaments. TPA does not induce the disassembly of the beta- and gamma-actin thin filaments of stress fibers in presumptive myoblasts or fibroblasts, nor does it block the reemergence of stress fibers in 72-h myosacs that have been depleted of all myofibrillar molecules. There are differences in where, when, and how myofibrillar alpha-actin and MHC are degraded and eliminated from TPA-myosacs. Though the anisodiametric myotubes have begun to retract into isodiametric myosacs after 5 h in TPA, staining with anti-MHC reveals normal tandem A bands. In contrast, staining with mAb to muscle actin fails to reveal tandem I bands. Instead, both mAb to muscle actin and rhophalloidin brilliantly stain numerous disk-like bodies approximately 3.0 micron in diameter. These muscle actin bodies do not fuse with one another, nor do they costain with anti-MHC. All muscle actin bodies and/or molecules disappear in 36-h myosacs. The collapse of A bands is first initiated in 10-h myosacs. Their loss correlates with the appearance of immense, amorphous MHC patches. MHC patches range from a few micrometers to over 60 micron in size. They do not costain with antimuscle actin or rho-phalloidin. While diminishing in number and fluorescence intensity, MHC aggregates are present in 30% of the 72-h myosacs. Myosacs removed from TPA rapidly elongate, and after 48 h display normal newly assembled myofibrils. TPA reversibly blocks incorporation of [35S]methionine into myofibrillar alpha-actin, MHC, myosin light chains 1 and 2, the tropomyosins, and troponin C. It does not block the synthesis of beta- or gamma-actins, the nonmyofibrillar MHC or light chains, tubulin, vimentin, desmin, or most household molecules.

Refined conditions for selective modifications of rabbit skeletal myosin light chains

Biochimie ◽  
1992 ◽  
Vol 74 (12) ◽  
pp. 1083-1090 ◽  
Author(s):  
J.M. Burgat ◽  
A. Roulet ◽  
R. Cardinaud
Keyword(s):  
Light Chains ◽  
Myosin Light Chains ◽  
Skeletal Myosin
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