Phosphate release and force generation in cardiac myocytes investigated with caged phosphate and caged calcium

Biophysical Journal
A Araujo, J W Walker

Abstract

The phosphate (P(i)) dissociation step of the cross-bridge cycle was investigated in skinned rat ventricular myocytes to examine its role in force generation and Ca(2+) regulation in cardiac muscle. Pulse photolysis of caged P(i) (alpha-carboxyl-2-nitrobenzyl phosphate) produced up to 3 mM P(i) within the filament lattice, resulting in an approximately exponential decline in steady-state tension. The apparent rate constant, k (rho i), increased linearly with total P(i) concentration (initial plus photoreleased), giving an apparent second-order rate constant for P(i) binding of 3100 M(-1) s(-1), which is intermediate in value between fast and slow skeletal muscles. A decrease in the level of Ca(2+) activation to 20% of maximum tension reduced k (rho i) by twofold and increased the relative amplitude by threefold, consistent with modulation of P(i) release by Ca2+. A three-state model, with separate but coupled transitions for force generation and P(i) dissociation, and a Ca(2+)-sensitive forward rate constant for force generation, was compatible with the data. There was no evidence for a slow phase of tension decline observed previously in fast skeletal fibers at low Ca(2+), suggesting differences in cooperative mechanisms in ca...Continue Reading

Citations

Jan 18, 2006·Heart Failure Reviews·David W Maughan
Mar 11, 2004·Journal of Molecular and Cellular Cardiology·Yasutake SaekiHaruo Sugi
Oct 24, 1998·Progress in Biophysics and Molecular Biology·P J HunterH E ter Keurs
Mar 9, 2010·PloS One·Young Soo Han, Ozgur Ogut
Jan 12, 2010·Journal of Molecular and Cellular Cardiology·Robert Stehle, Bogdan Iorga
Feb 28, 2013·Biophysical Journal·Asuka HatanoSeiryo Sugiura
Jan 30, 2004·Biophysical Journal·Hunter MartinRobert J Barsotti
Jun 24, 2000·Circulation Research·M RegnierP B Chase
Aug 16, 2006·Journal of Muscle Research and Cell Motility·Masataka Kawai, Shin'ichi Ishiwata
Apr 22, 2008·Journal of Muscle Research and Cell Motility·Masataka Kawai, Herbert R Halvorson
Dec 21, 2005·Journal of Veterinary Medicine. B, Infectious Diseases and Veterinary Public Health·M Vieira-PintoC Martins
Sep 21, 2005·American Journal of Physiology. Heart and Circulatory Physiology·Aaron C Hinken, Kerry S McDonald
Aug 19, 2007·American Journal of Physiology. Heart and Circulatory Physiology·Catalina NormanJonathan P Davis
Apr 16, 2004·American Journal of Physiology. Cell Physiology·Aaron C Hinken, Kerry S McDonald
Mar 23, 2001·The Journal of Biological Chemistry·C A MorrisE Homsher
Apr 4, 2000·Physiological Reviews·A M GordonM Regnier
Sep 18, 2017·Journal of Muscle Research and Cell Motility·Robert Stehle, Chiara Tesi
Oct 12, 2021·The Journal of Biological Chemistry·Samantha K Barrick, Michael J Greenberg

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