Acting Based Regulation of Smooth Muscle Contraction
Principal Investigator: JOSEPH CHALOVICH
Abstract: [unreadable] DESCRIPTION (provided by applicant): The regulation of contraction of smooth muscle differs in several respects from other muscle types. A detailed understanding of these differences could lead to new therapies for disorders of smooth muscle including hypertension, asthma, and disorders of the digestive system and urogenital system. In contrast to striated muscle, smooth muscle contains caldesmon, calponin and other actin-binding proteins, that inhibit ATPase activity and force production in model systems. We have identified a novel actin binding protein, fesselin that stimulates actin polymerization and inhibits actin activation of myosin ATPase activity. The various smooth muscle actin-binding proteins may function by altering (a) actin-myosin binding, (b) a transition between two actin-myosin complexes, (c) cell signaling, or (d) the plasticity of the cytoskeleton. Our first goal is to finalize the mechanism by which caldesmon inhibits smooth muscle contraction. The key questions with caldesmon are: (1) How much of the inhibition of contraction results from competitive inhibition of myosin binding? This will be answered by using rapid measurements of the fluorescence changes that occur when caldesmon and myosin bind to actin. (2) Does caldesmon also affect cross-bridge kinetics? This will be examined by studying the inhibition of release of fluorescent nucleotide derivatives from actin-S1 by caldesmon. (3) What is the function of caldesmon-myosin binding? We will collaborate with Dr. Gabrielle Pfitzer on the characterization of transgenic mice lacking part of the myosin-binding region of caldesmon. We will also study the structure of the caldesmon-myosin complex in collaboration with Dr. Peter Knight. Our second goal is to investigate the properties and function of fesselin. The relationship of fesselin to the synaptopodin family of actin-binding proteins will be investigated. We will study the mechanism of inhibition of actin-myosin ATPase activity. The most noteworthy activity of fesselin is its large acceleration of actin polymerization. Heavy emphasis will be placed on this activity and its reversal by Cacalmodulin. These studies will be conducted both in solution and in smooth muscle fiber systems. [unreadable] [unreadable]
Funding Period: 1985-04-01 - 2010-03-31
more information: NIH RePORT
- Avian synaptopodin 2 (fesselin) stabilizes myosin filaments and actomyosin in the presence of ATPNathanial L Kingsbury
Department of Biochemistry and Molecular Biology, Brody School of Medicine at East Carolina University, 600 Moye Boulevard, Greenville, North Carolina 27834 4300, United States
Biochemistry 52:7641-7. 2013..Data from this study suggest that fesselin stabilizes myosin filaments and tethers myosin to actin. These results support the view that one role of fesselin is to organize contractile units of myosin and actin. ..
- Organization of F-actin by Fesselin (avian smooth muscle synaptopodin 2)Mechthild M Schroeter
Institute of Vegetative Physiology, University of Cologne, Robert Koch Strasse 39, D 50931 Cologne, Germany
Biochemistry 52:4955-61. 2013..These results indicate a role of fesselin in organizing cellular actin. These and other results indicate that fesselin is part of a cellular actin organizing center. ..
- The C-terminus of troponin T is essential for maintaining the inactive state of regulated actinAndrew J Franklin
Department of Biochemistry and Molecular Biology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
Biophys J 102:2536-44. 2012..Replacing wild-type TnI with S45E TnI, that favors the inactive state, did not restore the fluorescence change. We conclude that TnT has a previously unrecognized role in forming the inactive state of regulated actin...
- Acrylodan-labeled smooth muscle tropomyosin reports differences in the effects of troponin and caldesmon in the transition from the active state to the inactive stateJoseph M Chalovich
Brody School of Medicine at East Carolina University, 5E 122 Brody Medical Sciences Building, Greenville, North Carolina 27834, USA
Biochemistry 50:6093-101. 2011..Although the measured rate constant appeared to reflect the rate-limiting transition for inactivation, it is unclear if the fluorescence change resulted from caldesmon binding, the movement of tropomyosin over actin, or both...
- Role of the tail in the regulated state of myosin 2Hyun Suk Jung
Institute of Molecular and Cellular Biology and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
J Mol Biol 408:863-78. 2011..Our results support the view that interactions between the heads and the distal tail perform a critical role in regulating activity of myosin 2 molecules through stabilizing the compact monomer conformation...
- Phosphorylation of caldesmon at sites between residues 627 and 642 attenuates inhibitory activity and contributes to a reduction in Ca2+-calmodulin affinitySvetlana S Hamden
Department of Biochemistry and Molecular Biology, Brody School of Medicine at East Carolina University, Greenville, North Carolina, USA
Biophys J 99:1861-8. 2010..Thus, the region between residues 627 and 642 may contribute to the overall regulation of caldesmon's activity...
- Localization of the actin-binding protein fesselin in chicken smooth muscleRandall H Renegar
Department of Anatomy and Cell Biology, Brody School of Medicine at East Carolina University, Greenville, NC, USA
Histochem Cell Biol 131:191-6. 2009..Infrequently, this banding pattern was observed in heart tissue as well. Localization at the Z-line of skeletal and cardiac muscle suggests a role in contraction of these tissues...
- In vitro characterization of native mammalian smooth-muscle protein synaptopodin 2Mechthild M Schroeter
Department of Biochemistry and Molecular Biology, Brody School of Medicine at East Carolina University, Greenville, NC 27834, USA
Biosci Rep 28:195-203. 2008..These properties are consistent with the proposed function of synaptopodin 2 in organizing the cytoskeleton...
- The actin binding protein, fesselin, is a member of the synaptopodin familyMechthild M Schroeter
Department of Biochemistry and Molecular Biology, Brody School of Medicine at East Carolina University, 600 Moye Blvd, Greenville, NC 27834, USA
Biochem Biophys Res Commun 371:582-6. 2008..We verified parts of the sequence by Edman analysis and by mass spectroscopy. Our results confirmed fesselin is homologous to human synaptopodin 2 and belongs to the synaptopodin family of proteins...
- Conservation of the regulated structure of folded myosin 2 in species separated by at least 600 million years of independent evolutionHyun Suk Jung
Institute of Molecular and Cellular Biology and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
Proc Natl Acad Sci U S A 105:6022-6. 2008..Conservation across such a large evolutionary distance suggests that this conformation is of fundamental functional importance...
- Fesselin is a natively unfolded proteinSvetlana S Khaymina
Departments of Biochemistry and Molecular Biology and Physics, Brody School of Medicine at East Carolina University, 600 Moye Boulevard, Greenville, North Carolina 27834, USA
J Proteome Res 6:3648-54. 2007..Calmodulin binding to fesselin altered the environment of the tryptophan residues so that they became less sensitive to the quencher acrylamide. These results show that fesselin is a natively unfolded protein...
- Smooth muscle alpha-actinin binds tightly to fesselin and attenuates its activity toward actin polymerizationMinh Pham
Brody School of Medicine at East Carolina University, 600 Moye Blvd, Greenville, NC 27834, USA
J Muscle Res Cell Motil 27:45-51. 2006..Fesselin accelerates the polymerization of actin. This activity of fesselin was attenuated by alpha-actinin. These observations support the role of fesselin in organizing the cytoskeleton...
- Fesselin binds to actin and myosin and inhibits actin-activated ATPase activityMechthild M Schroeter
Brody School of Medicine at East Carolina University, Greenville, NC 27834, USA
J Muscle Res Cell Motil 26:183-9. 2005..We also observed that fesselin could bind to smooth muscle myosin with muM affinity. Fesselin shares some similarities to caldesmon in binding to several other proteins and having multiple potential functions...