title: Fesselin binds to actin and myosin and inhibits actin-activated ATPase activity.
abstract: Fesselin is an actin binding protein that bundles actin filaments and accelerates nucleation of actin polymerization. The effect of fesselin on actin polymerization is regulated by Ca(++)-calmodulin. Because actin filaments serve both structural and contractile functions we also examined the effect of fesselin on activation of myosin S1 ATPase activity. Fesselin inhibited the activation of S1-catalyzed ATP hydrolysis in a similar manner in both the presence and absence of tropomyosin. This inhibition was unaffected by Ca(++)-calmodulin. Fesselin inhibited the binding of myosin-S1 to actin during steady-state ATP hydrolysis. Fesselin also displaced caldesmon from actin. S1 displaced fesselin from actin in the absence of nucleotide when the affinity of S1 for actin was much greater than the affinity of fesselin for actin. It is likely that fesselin and S1 share common binding sites on F-actin. 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.
authors.affiliation: Brody School of Medicine at East Carolina University, Greenville, NC 27834, USA. schroeterm@mail.ecu.edu
authors.forename: Mechthild M
authors.initials: MM
authors.lastname: Schroeter
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Chalovich
mesh_terms: D000199:Actins / Q000737:chemistry / Q000378:metabolism*; D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001667:Binding, Competitive; D002148:Calmodulin-Binding Proteins / Q000378:metabolism; D002384:Catalysis; D004789:Enzyme Activation / Q000187:drug effects; D006868:Hydrolysis; D008565:Membrane Proteins / Q000737:chemistry / Q000494:pharmacology / Q000502:physiology*; D008840:Microfilament Proteins / Q000737:chemistry / Q000494:pharmacology / Q000502:physiology*; D015879:Myosin Subfragments / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism; D009218:Myosins / Q000737:chemistry / Q000378:metabolism*; D011817:Rabbits; D014421:Turkey
chemical_list: D000199:Actins; D002148:Calmodulin-Binding Proteins; D008565:Membrane Proteins; D008840:Microfilament Proteins; D015879:Myosin Subfragments; C443099:fesselin; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; D009218:Myosins