Modulation of Myosin Function by Isoform-specific Properties of Saccharomyces cerevisiae and Muscle Tropomyosins Export

@article{citeulike:5418099, abstract = {Tropomyosin is an extended coiled-coil protein that influences actin function by binding longitudinally along thin filaments. The present work compares cardiac tropomyosin and the two tropomyosins from Saccharomyces cerevisiae, TPM1 and TPM2, that are much shorter than vertebrate tropomyosins. Unlike cardiac tropomyosin, the phase of the coiled-coil-forming heptad repeat of TPM2 is discontinuous; it is interrupted by a 4-residue deletion. TPM1 has two such deletions, which flank the 38-residue partial gene duplication that causes TPM1 to span five actins instead of the four of TPM2. Each of the three tropomyosin isoforms modulates actin-myosin interactions, with isoform-specific effects on cooperativity and strength of myosin binding. These different properties can be explained by a model that combines opposite effects, steric hindrance between myosin and tropomyosin when the latter is bound to a subset of its sites on actin, and also indirect, favorable interactions between tropomyosin and myosin, mediated by mutually promoted changes in actin. Both of these effects are influenced by which tropomyosin isoform is present. Finally, the tropomyosins have isoform-specific effects on in vitro sliding speed and on the myosin concentration dependence of this movement, suggesting that non-muscle tropomyosin isoforms exist, at least in part, to modulate myosin function. 10.1074/jbc.M104750200}, author = {Strand, James and Nili, Mahta and Homsher, Earl and Tobacman, Larry S.}, citeulike-article-id = {5418099}, citeulike-linkout-0 = {http://dx.doi.org/10.1074/jbc.M104750200}, citeulike-linkout-1 = {http://www.jbc.org/cgi/content/abstract/276/37/34832}, citeulike-linkout-2 = {http://view.ncbi.nlm.nih.gov/pubmed/11457840}, citeulike-linkout-3 = {http://www.hubmed.org/display.cgi?uids=11457840}, day = {7}, doi = {10.1074/jbc.M104750200}, journal = {J. Biol. Chem.}, keywords = {coiled-coils, tropomyosin}, month = {September}, number = {37}, pages = {34832--34839}, posted-at = {2009-08-11 21:40:15}, priority = {2}, title = {Modulation of Myosin Function by Isoform-specific Properties of Saccharomyces cerevisiae and Muscle Tropomyosins}, url = {http://dx.doi.org/10.1074/jbc.M104750200}, volume = {276}, year = {2001} }

TY - JOUR ID - citeulike:5418099 L3 - citeulike-article-id:5418099 N2 - Tropomyosin is an extended coiled-coil protein that influences actin function by binding longitudinally along thin filaments. The present work compares cardiac tropomyosin and the two tropomyosins from Saccharomyces cerevisiae, TPM1 and TPM2, that are much shorter than vertebrate tropomyosins. Unlike cardiac tropomyosin, the phase of the coiled-coil-forming heptad repeat of TPM2 is discontinuous; it is interrupted by a 4-residue deletion. TPM1 has two such deletions, which flank the 38-residue partial gene duplication that causes TPM1 to span five actins instead of the four of TPM2. Each of the three tropomyosin isoforms modulates actin-myosin interactions, with isoform-specific effects on cooperativity and strength of myosin binding. These different properties can be explained by a model that combines opposite effects, steric hindrance between myosin and tropomyosin when the latter is bound to a subset of its sites on actin, and also indirect, favorable interactions between tropomyosin and myosin, mediated by mutually promoted changes in actin. Both of these effects are influenced by which tropomyosin isoform is present. Finally, the tropomyosins have isoform-specific effects on in vitro sliding speed and on the myosin concentration dependence of this movement, suggesting that non-muscle tropomyosin isoforms exist, at least in part, to modulate myosin function. 10.1074/jbc.M104750200 IS - 37 JF - J. Biol. Chem. EP - 34839 TI - Modulation of Myosin Function by Isoform-specific Properties of Saccharomyces cerevisiae and Muscle Tropomyosins VL - 276 SP - 34832 KW - coiled-coils KW - tropomyosin AU - Strand, James AU - Nili, Mahta AU - Homsher, Earl AU - Tobacman, Larry PY - 2001/09/07/ UR - http://dx.doi.org/10.1074/jbc.M104750200 ER -