Striated Muscle Twitchin of Bivalves has “Catchability”, the Ability to Bind Thick Filaments Tightly to Thin Filaments, Representing the Catch State

Tsutsui, Yasutaka; Matsumoto, Yoshio; Oiwa, Kazuhiro; Yamada, Akira

doi:10.1016/j.jmb.2006.10.006

Cited by 20 publications

(8 citation statements)

References 48 publications

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“…On the other hand, the sensitivity to pH may be associated only with the intact contractile system. Recently, it was found that striated muscles from oyster and scallop contain twitchin and this regulates interaction between thin and thick filaments at low [Ca 2+ ] (Tsutsui et al, 2007), as it does in molluscan catch muscle. These results suggest a similar role for twitchin in striated and smooth molluscan muscle and the molecular scheme outlined above may be applicable to both muscle types.…”

Section: Discussionmentioning

confidence: 99%

Unphosphorylated twitchin forms a complex with actin and myosin that may contribute to tension maintenance in catch

Funabara

Hamamoto

Yamamoto

et al. 2007

Journal of Experimental Biology

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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.

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Section: Discussionmentioning

confidence: 99%

Unphosphorylated twitchin forms a complex with actin and myosin that may contribute to tension maintenance in catch

Funabara

Hamamoto

Yamamoto

et al. 2007

Journal of Experimental Biology

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“…Exhaustion or ''fatigue'' is defined here when scallops cannot respond to further stimulations and remain closed (Chih and Ellington, 1983;Brokordt et al, 2006). Indeed, the permanent closure of the valves is supported by the catch contraction of the tonic muscle, which requires almost no energy (Tsutsui et al, 2007). Predation would be more likely to occur when a resting (recovering from previous exercise, that did not induced exhaustion) or exhausted scallop is captured by M. gelatinosus.…”

Section: Introductionmentioning

confidence: 99%

Effects of the toxic dinoflagellate Alexandrium catenella on histopathogical and escape responses of the Northern scallop Argopecten purpuratus

et al. 2012

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“…There is some evidence that twitchin from molluscan striated muscles that are not catch muscles also mediates binding of thick and thin filaments in vitro (Tsutsui et al 2007). In addition, a tethering function of twitchin could be responsible for its phosphorylation-mediated regulation of relaxation rate in Aplysia accessory radula closer muscles (Probst et al 1994), and could play a role in the constant twitching of body wall muscles associated with its mutation in C. elegans (Moerman et al 1988).…”

Section: Discussionmentioning

confidence: 99%

A force-activated kinase in a catch smooth muscle

Butler

Siegman

2011

J Muscle Res Cell Motil

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Permeabilized anterior byssus retractor muscles (ABRM) from Mytilus edulis were used as a simple system to test whether there is a stretch dependent activation of a kinase as has been postulated for titin and the mini-titin twitchin. The ABRM is a smooth muscle that shows catch, a condition of high force maintenance and resistance to stretch following stimulation when the intracellular Ca++ concentration has diminished to sub-maximum levels. In the catch state twitchin is unphosphorylated, and the muscle maintains force without myosin crossbridge cycling through what is likely a twitchin mediated tether between thick and thin filaments. In catch, a small change in length results in a large change in force. The phosphorylation state of an added peptide, a good substrate for molluscan twitchin kinase, with the sequence KKRAARATSNVFA was used as a measure of kinase activation. We find that there is about a two-fold increase in phosphorylation of the added peptide with a 10% stretch of the ABRM in catch. The increased phosphorylation is due to activation of a kinase rather than to an inhibition of a phosphatase. The extent of phosphorylation of the peptide is decreased when twitchin is phosphorylated and catch force is not present. However, there is also a large increase in peptide phosphorylation when the muscle is activated in pCa 5, and the catch state does not exist. The force-sensitive kinase activity is decreased by ML-9 and ML-7 which are inhibitors of twitchin kinase, but not by the Rho kinase inhibitor Y-27632. There is no detectable phosphorylation of myosin light chains, but the phosphorylation of twitchin increases by a small, but significant extent with stretch. It is possible that twitchin senses force output resulting in a force-sensitive twitchin kinase activity that results in autophosphorylation of twitchin on site(s) other than those responsible for relaxation of catch.

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Striated Muscle Twitchin of Bivalves has “Catchability”, the Ability to Bind Thick Filaments Tightly to Thin Filaments, Representing the Catch State

Cited by 20 publications

References 48 publications

Unphosphorylated twitchin forms a complex with actin and myosin that may contribute to tension maintenance in catch

Unphosphorylated twitchin forms a complex with actin and myosin that may contribute to tension maintenance in catch

Effects of the toxic dinoflagellate Alexandrium catenella on histopathogical and escape responses of the Northern scallop Argopecten purpuratus

A force-activated kinase in a catch smooth muscle

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