RAPID TURNOVER OF MYOSIN LIGHT-CHAIN PHOSPHATE DURING CROSS-BRIDGE CYCLING IN SMOOTH-MUSCLE

被引:10
作者
BUTLER, TM
NARAYAN, SR
MOOERS, SU
SIEGMAN, MJ
机构
来源
AMERICAN JOURNAL OF PHYSIOLOGY-CELL PHYSIOLOGY | 1994年 / 267卷 / 04期
关键词
PHOSPHATASE; CAGED ADENOSINE TRIPHOSPHATE; PHOSPHORYLATION; CONTRACTION;
D O I
10.1152/ajpcell.1994.267.4.C1160
中图分类号
Q2 [细胞生物学];
学科分类号
071009 ; 090102 ;
摘要
The rate of phosphatase-mediated dephosphorylation of the regulatory light chain of smooth muscle myosin was determined under nearly steady-state conditions in permeabilized muscles, from the time course of incorporation of P-33-labeled phosphate into the light chain after the photolytic release of [gamma-P-33]ATP from high specific activity caged [gamma-P-33]ATP. The extent of myosin light chain phosphorylation is unchanged, and, if the kinase and phosphatase reactions are irreversible, the rate constant for the exponential increase in P-33 in the light chain is equal to the rate constant for the phosphatase reaction. Under activated conditions (pCa 4.5) at 20 degrees C, the incorporation of P-33 into similar to 80% of the phosphorylated light chain is fit by a single exponential with a rate constant of 0.37 s(-1). ATP usage due to phosphorylation and dephosphorylation of the light chain is about one-third of the suprabasal energy requirement. The high phosphatase rate constant suggests that dephosphorylation of the light chain is rapid enough to interact with and potentially modify the completion of the cross-bridge cycle.
引用
收藏
页码:C1160 / C1166
页数:7
相关论文
共 35 条
[1]   EXCHANGE OF 20-KDA MYOSIN LIGHT CHAIN-BOUND PHOSPHATE DURING SUSTAINED CONTRACTION OF ARTERIAL SMOOTH-MUSCLE [J].
BARANY, M ;
ROKOLYA, A ;
BARANY, K .
ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS, 1991, 287 (01) :199-203
[2]   CHEMICAL ENERGY USAGE DURING SHORTENING AND WORK PRODUCTION IN MAMMALIAN SMOOTH-MUSCLE [J].
BUTLER, TM ;
SIEGMAN, MJ ;
MOOERS, SU .
AMERICAN JOURNAL OF PHYSIOLOGY, 1983, 244 (03) :C234-C242
[3]   ADP RELEASE FROM MYOSIN IN PERMEABILIZED SMOOTH-MUSCLE [J].
BUTLER, TM ;
PACIFICO, DS ;
SIEGMAN, MJ .
AMERICAN JOURNAL OF PHYSIOLOGY, 1989, 256 (01) :C59-C66
[4]   MYOSIN-PRODUCT COMPLEX IN THE RESTING STATE AND DURING RELAXATION OF SMOOTH-MUSCLE [J].
BUTLER, TM ;
SIEGMAN, MJ ;
MOOERS, SU ;
NARAYAN, SR .
AMERICAN JOURNAL OF PHYSIOLOGY, 1990, 258 (06) :C1092-C1099
[5]   SLOWING OF CROSS-BRIDGE CYCLING IN SMOOTH-MUSCLE WITHOUT EVIDENCE OF AN INTERNAL LOAD [J].
BUTLER, TM ;
SIEGMAN, MJ ;
MOOERS, SU .
AMERICAN JOURNAL OF PHYSIOLOGY, 1986, 251 (06) :C945-C950
[6]   REGULATION OF ACTIN-ACTIVATED ATP HYDROLYSIS BY ARTERIAL MYOSIN [J].
CHACKO, S ;
ROSENFELD, A .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA-BIOLOGICAL SCIENCES, 1982, 79 (02) :292-296
[7]   MYOSIN PHOSPHORYLATION AND THE CROSS-BRIDGE CYCLE IN ARTERIAL SMOOTH-MUSCLE [J].
DILLON, PF ;
AKSOY, MO ;
DRISKA, SP ;
MURPHY, RA .
SCIENCE, 1981, 211 (4481) :495-497
[8]   MYOSIN DEPHOSPHORYLATION DURING RAPID RELAXATION OF HOG CAROTID-ARTERY SMOOTH-MUSCLE [J].
DRISKA, SP ;
STEIN, PG ;
PORTER, R .
AMERICAN JOURNAL OF PHYSIOLOGY, 1989, 256 (02) :C315-C321
[9]  
DRISKA SP, 1987, REGULATION CONTRACTI, P387
[10]   MYOSIN PHOSPHORYLATION AND REGULATION OF CROSS-BRIDGE CYCLE IN TRACHEAL SMOOTH-MUSCLE [J].
GERTHOFFER, WT ;
MURPHY, RA .
AMERICAN JOURNAL OF PHYSIOLOGY, 1983, 244 (03) :C182-C187