4anj
From Proteopedia
MYOSIN VI (MDinsert2-GFP fusion) PRE-POWERSTROKE STATE (MG.ADP.AlF4)
Structural highlights
FunctionMYO6_PIG Myosins are actin-based motor molecules with ATPase activity. Unconventional myosins serve in intracellular movements. Myosin 6 is a reverse-direction motor protein that moves towards the minus-end of actin filaments. Has slow rate of actin-activated ADP release due to weak ATP binding. Functions in a variety of intracellular processes such as vesicular membrane trafficking and cell migration. Required for the structural integrity of the Golgi apparatus via the p53-dependent pro-survival pathway. Appears to be involved in a very early step of clathrin-mediated endocytosis in polarized epithelial cells. May act as a regulator of F-actin dynamics. May play a role in transporting DAB2 from the plasma membrane to specific cellular targets. Required for structural integrity of inner ear hair cells (By similarity).[1] GFP_AEQVI Energy-transfer acceptor. Its role is to transduce the blue chemiluminescence of the protein aequorin into green fluorescent light by energy transfer. Fluoresces in vivo upon receiving energy from the Ca(2+)-activated photoprotein aequorin. Publication Abstract from PubMedMyosin VI is the only known reverse-direction myosin motor. It has an unprecedented means of amplifying movements within the motor involving rearrangements of the converter subdomain at the C terminus of the motor and an unusual lever arm projecting from the converter. While the average step size of a myosin VI dimer is 30-36 nm, the step size is highly variable, presenting a challenge to the lever arm mechanism by which all myosins are thought to move. Herein, we present structures of myosin VI that reveal regions of compliance that allow an uncoupling of the lead head when movement is modeled on actin. The location of the compliance restricts the possible actin binding sites and predicts the observed stepping behavior. The model reveals that myosin VI, unlike plus-end directed myosins, does not use a pure lever arm mechanism, but instead steps with a mechanism analogous to the kinesin neck-linker uncoupling model. Processive Steps in the Reverse Direction Require Uncoupling of the Lead Head Lever Arm of Myosin VI.,Menetrey J, Isabet T, Ropars V, Mukherjea M, Pylypenko O, Liu X, Perez J, Vachette P, Sweeney HL, Houdusse AM Mol Cell. 2012 Aug 29. PMID:22940248[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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