Catch muscle myorod modulates ATPase activity of Myosin in a phosphorylation-dependent way.
Myorod is expressed exclusively in molluscan catch muscle and localizes on the surface of thick filaments together with twitchin and myosin. Myorod is an alternatively spliced product of the myosin heavy-chain gene that contains the C-terminal rod part of myosin and a unique N-terminal domain. The unique domain is a target for phosphorylation by gizzard smooth myosin light chain kinase (smMLCK) and, perhaps, molluscan twitchin, which contains a MLCK-like domain. To elucidate the role of myorod and its phosphorylation in the catch muscle, the effect of chromatographically purified myorod on the actin-activated Mg2+-ATPase activity of myosin was studied. We found that phosphorylation at the N-terminus of myorod potentiated the actin-activated Mg2+-ATPase activity of mussel and rabbit myosins. This potentiation occurred only if myorod was phosphorylated and introduced into the ATPase assay as a co-filament with myosin. We suggest that myorod could be related to the catch state, a function specific to molluscan muscle.
A.V. Zhirmunsky Institute of Marine Biology, Far East Branch of the Russian Academy of Sciences, Vladivostok, Russia; School of Biomedicine, Far Eastern Federal University, Vladivostok, Russia.
Oleg S
OS
Matusovsky
A.V. Zhirmunsky Institute of Marine Biology, Far East Branch of the Russian Academy of Sciences, Vladivostok, Russia.
Ulyana V
UV
Shevchenko
A.V. Zhirmunsky Institute of Marine Biology, Far East Branch of the Russian Academy of Sciences, Vladivostok, Russia.
Galina G
GG
Matusovskaya
Institute for Biomedical Aging Research, Austrian Academy of Sciences, Innsbruck, Austria.
Apolinary
A
Sobieszek
A.V. Zhirmunsky Institute of Marine Biology, Far East Branch of the Russian Academy of Sciences, Vladivostok, Russia.
Anna V
AV
Dobrzhanskaya
A.V. Zhirmunsky Institute of Marine Biology, Far East Branch of the Russian Academy of Sciences, Vladivostok, Russia.
Nikolay S
NS
Shelud'ko
D000205:Actomyosin / Q000378:metabolism; D000818:Animals; D049872:Bivalvia / Q000378:metabolism / Q000502:physiology; D017301:Ca(2+) Mg(2+)-ATPase / Q000378:metabolism*; D011232:Chemical Precipitation; D009119:Muscle Contraction / Q000502:physiology; D009124:Muscle Proteins / Q000302:isolation & purification / Q000378:metabolism* / Q000502:physiology; D009130:Muscle, Smooth / Q000201:enzymology / Q000378:metabolism / Q000502:physiology*; D009218:Myosins / Q000378:metabolism*; D010766:Phosphorylation
D009124:Muscle Proteins; D000205:Actomyosin; D017301:Ca(2+) Mg(2+)-ATPase; D009218:Myosins