Actin and myosin-linked calcium regulation in the nematode Caenorhabditis elegans. Biochemical and structural properties of native filaments and purified proteins

Harris, Harriet E.; Tso, Man-Yin W.; Epstein, Henry F.

doi:10.1021/bi00624a008

Cited by 47 publications

(24 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The predicted size of Ov-TMY-1 from sequence data is 33.2 kDa, suggesting that it may be posttranslationally modified. However, several tropomyosins have been recorded as migrating anomalously on SDS͞PAGE gels, including those of C. elegans (37), Ascaris lumbricoides (38), and T. colubriformis (14). In the case of T. colubriformis, glycanase treatment of native tropomyosin indicated that it was not modified with sugars (14).…”

Section: Resultsmentioning

confidence: 99%

Tropomyosin implicated in host protective responses to microfilariae in onchocerciasis

Jenkins

Taylor

Gilvary

et al. 1998

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

A cDNA from adult female Onchocerca volvulus encoding the C-terminal portion of a tropomyosin isoform (termed MOv-14) has been shown previously to confer protective immunity in rodent models of onchocerciasis. The full-length sequence (designated Ov-tmy-1) obtained by PCR amplification, codes for a protein of 33 kDa and shares 91% identity with tropomyosins from other nematodes, falling to 57% identity with human ␣-tropomyosin. Ov-TMY-1 migrates with an apparent molecular mass of 42 kDa on SDS͞PAGE and is present in all life-cycle stages, as determined by immunoblotting. Immunogold electron microscopy identified antigenic sites within muscle blocks and the cuticle of microfilariae and infective larvae. Anti-MOv14 antibodies were abundant in mice exhibiting serum-transferable protection against microfilariae conferred by vaccination with a PBSsoluble parasite extract. In contrast, little or no MOv14-specific antibody was present in mice inoculated with live microfilariae, in which resistance is mediated by antibodyindependent mechanisms. In human infections, there was an inverse correlation between anti-tropomyosin IgG levels and densities of microfilariae in the skin. Seropositivity varied with the relative endemicity of infection. An immunodominant B cell epitope within Ov-TMY-1 (AQLLAEEADRKYD) was mapped to the N terminus of the MOv14 protein by using sera from protectively vaccinated mice. Intriguingly, the sequence coincides with an IgE-binding epitope within shrimp tropomyosin, believed to be responsible for hypersensitivity in individuals exhibiting allergy to shellfish. IgG and IgE antibodies reacting with the O. volvulus epitope were detected in human infections. It is concluded that antibody responses to tropomyosin may be important in limiting microfilarial densities in a proportion of individuals with onchocerciasis and have the potential to mediate hypersensitivity reactions to dead microfilariae, raising the possibility of a link with the immunopathology of infection.

show abstract

Section: Resultsmentioning

confidence: 99%

Tropomyosin implicated in host protective responses to microfilariae in onchocerciasis

Jenkins

Taylor

Gilvary

et al. 1998

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…Therefore, it is possible that the activity of myosin is regulated by a separate mechanism, which may prevent hypercontraction when the TM-TN system is inhibited. Indeed, biochemical studies on isolated C. elegans myosin and actin demonstrated that C. elegans has both actin-and myosinlinked regulatory systems for the actomyosin activity (Harris et al, 1977). Regulatory myosin light chains often play critical roles in the regulation of myosin activity, although the regulatory mechanisms are various.…”

Section: Discussionmentioning

confidence: 99%

Tropomyosin and Troponin Are Required for Ovarian Contraction in theCaenorhabditis elegansReproductive System

Ono

2004

MBoC

View full text Add to dashboard Cite

Ovulation in the nematode Caenorhabditis elegans is coordinated by interactions between the somatic gonad and germ cells. Myoepithelial sheath cells of the proximal ovary are smooth muscle-like cells, but the regulatory mechanism of their contraction is unknown. We show that contraction of the ovarian muscle requires tropomyosin and troponin, which are generally major actin-linked regulators of contraction of striated muscle. RNA interference of tropomyosin or troponin C caused sterility by inhibiting ovarian contraction that is required for expelling mature oocytes into the spermatheca where fertilization takes place, thus causing accumulation of endomitotic oocytes in the ovary. Tropomyosin and troponin C were associated with actin filaments in the myoepithelial sheath, and the association of troponin C with actin was dependent on tropomyosin. A mutation in the actin depolymerizing factor/cofilin gene suppressed the ovulation defects by RNA interference of tropomyosin or troponin C. These results strongly suggest that tropomyosin and troponin are the actin-linked regulators for contraction of ovarian muscle in the C. elegans reproductive system.

show abstract

“…The regulatory MLCs of skeletal and cardiac muscle are phosphorylated, but this appears to play a minor, modulatory role in the contractile cycle (35,50). The muscles of many invertebrates, including C. elegans, exhibit elements of both myosin-based and actin-based control (23,36). Genetic manipulation of MLC proteins will likely be required for a complete understanding of their in vivo * Corresponding author.…”

mentioning

confidence: 99%

Regulatory myosin light-chain genes of Caenorhabditis elegans.

Cummins¹,

Anderson²

1988

Mol. Cell. Biol.

View full text Add to dashboard Cite

We have cloned and analyzed the Caenorhabditis elegans regulatory myosin light-chain genes. C. elegans contains two such genes, which we have designated mic-i and mk-2. The two genes are separated by 2.6 kilobases and are divergently transcribed. We determined the complete nucleotide sequences of both mlk-i and mlc-2. A single, conservative amino acid substitution distinguishes the sequences of the two proteins. The C. elegans proteins are strongly homologous to regulatory myosin light chains of Drosophila melanogaster and vertebrates and weakly homologous to a superfamily of eucaryotic calcium-binding proteins. Both mlk-i and mlk-2 encode abundant mRNAs. We mapped the 5' termini of these transcripts by using primer extension sequencing of mRNA templates. mic-i mRNAs initiate within conserved hexanucleotides at two different positions, located at -28 and -38 relative to the start of translation. The 5' terminus of mlk-2 mRNA is not encoded in the 4.8-kilobase genomic region upstream of mlc-2. Rather, mlc-2 mRNA contains at its 5' end a short, untranslated leader sequence that is identical to the trans-spliced leader sequence of three C. elegans actin genes.

show abstract

Actin and myosin-linked calcium regulation in the nematode Caenorhabditis elegans. Biochemical and structural properties of native filaments and purified proteins

Cited by 47 publications

References 33 publications

Tropomyosin implicated in host protective responses to microfilariae in onchocerciasis

Tropomyosin implicated in host protective responses to microfilariae in onchocerciasis

Tropomyosin and Troponin Are Required for Ovarian Contraction in theCaenorhabditis elegansReproductive System

Regulatory myosin light-chain genes of Caenorhabditis elegans.

Contact Info

Product

Resources

About