Load-dependent mechanism of nonmuscle myosin 2.

@article{citeulike:1375303, abstract = {Loads on molecular motors regulate and coordinate their function. In a study that directly measures properties of internally strained myosin 2 heads bound to actin, we find that human nonmuscle myosins 2A and 2B show marked load-dependent changes in kinetics of ADP release but not in nucleotide binding. We show that the ADP release rate constant is increased 4-fold by the assisting load on one head and decreased 5-fold (for 2A) or 12-fold (for 2B) by the resisting load on the other. Thus these myosins, especially 2B, have marked mechanosensitivity of product release. By regulating the actin attachment of myosin heads, this provides a basis for energy-efficient tension maintenance without obstructing cellular contractility driven by other motors such as smooth muscle myosin. Whereas forward load accelerates the cycle of interaction with actin, resistive load increases duty ratio to favor tension maintenance by two-headed attachment.}, address = {Laboratory of Molecular Physiology, National Heart, Lung, and Blood Institute, Bethesda, MD 20892-8015;}, author = {Kov\'{a}cs, Mih\'{a}ly and Thirumurugan, Kavitha and Knight, Peter J J. and Sellers, James R R. }, citeulike-article-id = {1375303}, doi = {10.1073/pnas.0701181104}, issn = {0027-8424}, journal = {Proc Natl Acad Sci U S A}, keywords = {adp, experiment, motor, myosin, strain}, month = {June}, posted-at = {2007-06-10 04:13:08}, priority = {2}, title = {Load-dependent mechanism of nonmuscle myosin 2.}, url = {http://dx.doi.org/10.1073/pnas.0701181104}, year = {2007} }

TY - JOUR ID - citeulike:1375303 L3 - citeulike-article-id:1375303 TI - Load-dependent mechanism of nonmuscle myosin 2. JF - Proc Natl Acad Sci U S A AD - Laboratory of Molecular Physiology, National Heart, Lung, and Blood Institute, Bethesda, MD 20892-8015; SN - 0027-8424 N2 - Loads on molecular motors regulate and coordinate their function. In a study that directly measures properties of internally strained myosin 2 heads bound to actin, we find that human nonmuscle myosins 2A and 2B show marked load-dependent changes in kinetics of ADP release but not in nucleotide binding. We show that the ADP release rate constant is increased 4-fold by the assisting load on one head and decreased 5-fold (for 2A) or 12-fold (for 2B) by the resisting load on the other. Thus these myosins, especially 2B, have marked mechanosensitivity of product release. By regulating the actin attachment of myosin heads, this provides a basis for energy-efficient tension maintenance without obstructing cellular contractility driven by other motors such as smooth muscle myosin. Whereas forward load accelerates the cycle of interaction with actin, resistive load increases duty ratio to favor tension maintenance by two-headed attachment. KW - adp KW - experiment KW - motor KW - myosin KW - strain AU - Kovács, Mihály AU - Thirumurugan, Kavitha AU - Knight, Peter J AU - Sellers, James R PY - 2007/06/04/ UR - http://dx.doi.org/10.1073/pnas.0701181104 ER -