Unphosphorylated twitchin forms a complex with actin and myosin that may contribute to tension maintenance in catch
| Autor: | Shugo Watabe, Daisuke Funabara, David J. Hartshorne, Miki Ueda, Koji Yamamoto, Satoshi Kanoh, Chieko Hamamoto, Akinori Inoue, Suechika Suzuki, Rika Osawa |
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| Rok vydání: | 2007 |
| Předmět: |
Models
Molecular Myosin light-chain kinase Physiology Molecular Sequence Data Muscle Proteins myosin Tropomyosin macromolecular substances Myosins Aquatic Science Biology Article Myosin head ABRM Myosin Animals Amino Acid Sequence Phosphorylation Binding site catch contraction Molecular Biology Peptide sequence Ecology Evolution Behavior and Systematics Actin Binding Sites Muscles Actin cytoskeleton Actins Biomechanical Phenomena Actin Cytoskeleton Protein Transport Biochemistry Mollusca Muscle Tonus Insect Science Biophysics Mutant Proteins Animal Science and Zoology Ca(2+) Mg(2+)-ATPase twitchin Peptides actin Chickens Protein Binding |
| Zdroj: | Journal of Experimental Biology. 210:4399-4410 |
| ISSN: | 1477-9145 0022-0949 |
| DOI: | 10.1242/jeb.008722 |
| Popis: | SUMMARY Molluscan smooth muscle can maintain tension over extended periods with little energy expenditure, a process termed catch. Catch is thought to be regulated by phosphorylation of a thick filament protein, twitchin, and involves two phosphorylation sites, D1 and D2, close to the N and C termini,respectively. This study was initiated to investigate the role of the D2 site and its phosphorylation in the catch mechanism. A peptide was constructed containing the D2 site and flanking immunoglobulin (Ig) motifs. It was shown that the dephosphorylated peptide, but not the phosphorylated form, bound to both actin and myosin. The binding site on actin was within the sequence L10 to P29. This region also binds to loop 2 of the myosin head. The dephosphorylated peptide linked myosin and F-actin and formed a trimeric complex. Electron microscopy revealed that twitchin is distributed on the surface of the thick filament with an axial periodicity of 36.25 nm and it is suggested that the D2 site aligns with the myosin heads. It is proposed that the complex formed with the dephosphorylated D2 site of twitchin, F-actin and myosin represents a component of the mechanical linkage in catch. |
| Databáze: | OpenAIRE |
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