TY - JOUR
T1 - Effect of diastolic pressure on MLC2v phosphorylation in the rat left ventricle
AU - Hidalgo, Carlos
AU - Wu, Yiming
AU - Peng, Jun
AU - Siems, William F.
AU - Campbell, Kenneth B.
AU - Granzier, Henk
PY - 2006/12/15
Y1 - 2006/12/15
N2 - The effect of passive muscle stretch on the extent of MLC2v phosphorylation was investigated. We used an isolated rat heart preparation and controlled the passive pressure of the left ventricle (LV) at 0 or 15 mmHg. The hearts were flash frozen and the LV free wall was split into epicardial and the endocardial halves. The samples were solubilized using a novel method that minimizes changes in the phosphate content of MLC2v under non-denaturing conditions. The proteins were separated by urea glycerol PAGE and identified by mass spectrometry and Western blots. At 0 mmHg passive pressure, the extent of MLC2v phosphorylation of the epicardium (34.1 ± 1.7%) was the same as that of the endocardium (35.3 ± 3.4%). At 15 mmHg passive pressure, we found a significant increase in MLC2v phosphorylation in the epicardium (to 41.5 ± 2.0%) and a significant reduction in the endocardium (to 24.2 ± 1.2%), giving rise to a gradient in the extent of MLC2v phosphorylation from epicardium (high) to endocardium (low). These changes in MLC2v phosphorylation that take place in response to increased diastolic pressure are likely to impact on the calcium sensitivity of actomyosin interaction (with an increased sensitivity towards the epicardium) and may play a role in the Frank-Starling mechanism of the heart.
AB - The effect of passive muscle stretch on the extent of MLC2v phosphorylation was investigated. We used an isolated rat heart preparation and controlled the passive pressure of the left ventricle (LV) at 0 or 15 mmHg. The hearts were flash frozen and the LV free wall was split into epicardial and the endocardial halves. The samples were solubilized using a novel method that minimizes changes in the phosphate content of MLC2v under non-denaturing conditions. The proteins were separated by urea glycerol PAGE and identified by mass spectrometry and Western blots. At 0 mmHg passive pressure, the extent of MLC2v phosphorylation of the epicardium (34.1 ± 1.7%) was the same as that of the endocardium (35.3 ± 3.4%). At 15 mmHg passive pressure, we found a significant increase in MLC2v phosphorylation in the epicardium (to 41.5 ± 2.0%) and a significant reduction in the endocardium (to 24.2 ± 1.2%), giving rise to a gradient in the extent of MLC2v phosphorylation from epicardium (high) to endocardium (low). These changes in MLC2v phosphorylation that take place in response to increased diastolic pressure are likely to impact on the calcium sensitivity of actomyosin interaction (with an increased sensitivity towards the epicardium) and may play a role in the Frank-Starling mechanism of the heart.
KW - Calcium sensitivity
KW - Frank-Starling relation
KW - Myosin regulatory light chain
KW - Passive muscle stretch
KW - Post-translational modification
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U2 - 10.1016/j.abb.2006.06.026
DO - 10.1016/j.abb.2006.06.026
M3 - Article
C2 - 16949549
AN - SCOPUS:33845312673
VL - 456
SP - 216
EP - 223
JO - Archives of Biochemistry and Biophysics
JF - Archives of Biochemistry and Biophysics
SN - 0003-9861
IS - 2
ER -