UniProtSummary | FUNCTION:SwissProt:P12883#Musclecontraction. SIZE:1935aminoacids;223097Da SUBUNIT:Musclemyosinisahexamericproteinthatconsistsof2heavychainsubunits(MHC),2alkalilightchainsubunits(MLC)and2regulatorylightchainsubunits(MLC-2). SUBCELLULARLOCATION:Cytoplasm,myofibril.Note=Thickfilamentsofthemyofibrils. DOMAIN:SwissProt:P12883Therodliketailsequenceishighlyrepetitive,showingcyclesofa28-residuerepeatpatterncomposedof4heptapeptides,characteristicforalpha-helicalcoiledcoils. DISEASE:SwissProt:P12883#DefectsinMYH7arethecauseoffamilialhypertrophiccardiomyopathytype1(CMH1)[MIM:192600];alsodesignatedFHCorHCM.Hypertrophiccardiomyopathyisaheartdisordercharacterizedbyventricularhypertrophy,whichisusuallyasymmetricandofteninvolvestheinterventricularseptum.Theprevalenceofthediseaseinthegeneralpopulationis0.2%.FHCisclinicallyheterogeneous,withinter-andintrafamilialvariationsrangingfrombenigntomalignantformswithhighriskofcardiacfailureandsuddencardiacdeath.&DefectsinMYH7arethecauseofmyosinstoragemyopathy[MIM:608358].Inthisdisorder,musclebiopsyshowstype1fiberpredominanceandincreasedinterstitialfatandconnectivetissue.Inclusionbodiesconsistingofthebetacardiacmyosinheavychainarepresentinthemajorityoftype1fibers,butnotintype2fibers.&DefectsinMYH7areacauseofdilatedcardiomyopathy(CMD)[MIM:115200].CMDisadisordercharacterizedbycardiacdilationandreducedsystolicfunction.&DefectsinMYH7arethecauseofLaingearly-onsetdistalmyopathy(MPD1)[MIM:160500].MPD1isanautosomaldominantdisorderwhichdiffersfromotherdistalmyopathiesinthatonsetisasearlyas4yearsofage.SelectiveweaknessoftheanteriortibialmusclesisfollowedbyweaknessofthefingerextensorsandselectedproximalmusclegroupssuchasthehipaBDuctorsandrotators,theshoulderabductorsandthesternocleidomastoids. SIMILARITY:Contains1IQdomain.&Contains1myosinhead-likedomain. MISCELLANEOUS:Eachmyosinheavychaincanbesplitinto1lightmeromyosin(LMM)and1heavymeromyosin(HMM).Itcanlaterbesplitfurtherinto2globularsubfragments(S1)and1rod-shapedsubfragment(S2).&Thecardiacalphaisoformisa"fast"ATPasemyosin,whilethebetaisoformisa"slow"ATPase. |