title: Ca(2+)-dependent effects of C-protein on the actin-activated ATPase of phosphorylated and dephosphorylated skeletal muscle myosin.
abstract: The effects of C-protein on actin-activated myosin ATPase depending on Ca(2+)-level and LC2-phosphorylation were studied. Column-purified myosin and non-regulated actin were used. At ionic strength of 0.06 C-protein inhibits actomyosin ATPase activity both in the presence and in the absence of calcium, more effective in the case of dephosphorylated myosin. For this myosin, at mu = 0.12 C-protein activates actomyosin ATPase at pCa4, but slightly inhibits at pCa8. No such effects have been observed in the case of phosphorylated myosin. The possibility of coordinative action of LC2-chains and C-protein in regulatory mechanism of skeletal muscle contraction is discussed.
authors.affiliation: Institute of Theoretical and Experimental Biophysics, USSR Academy of Sciences, Pushchino, Moscow.
authors.forename: S N
authors.initials: SN
authors.lastname: Udaltsov
authors.forename: D
authors.initials: D
authors.lastname: Stepkowski
authors.forename: N A
authors.initials: NA
authors.lastname: Freydina
authors.forename: Z A
authors.initials: ZA
authors.lastname: Podlubnaya
mesh_terms: D000199:Actins / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D002352:Carrier Proteins; D004789:Enzyme Activation / Q000187:drug effects; D009119:Muscle Contraction / Q000502:physiology*; D009124:Muscle Proteins / Q000378:metabolism*; D009218:Myosins / Q000378:metabolism*; D010766:Phosphorylation; D011817:Rabbits; D000099163:Myosin Binding Protein C
chemical_list: D000199:Actins; D002118:Calcium; D002352:Carrier Proteins; D009124:Muscle Proteins; D009218:Myosins; D000099163:Myosin Binding Protein C