Structural highlights
Function[MYO5A_CHICK] Processive actin-based motor that can move in large steps approximating the 36-nm pseudo-repeat of the actin filament. Involved in melanosome transport. Also mediates the transport of vesicles to the plasma membrane. May also be required for some polarization process involved in dendrite formation (By similarity). Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedUnconventional myosin V (myoV) is an actin-based molecular motor that has a key function in organelle and mRNA transport, as well as in membrane trafficking. MyoV was the first member of the myosin superfamily shown to be processive, meaning that a single motor protein can 'walk' hand-over-hand along an actin filament for many steps before detaching. Full-length myoV has a low actin-activated MgATPase activity at low [Ca2+], whereas expressed constructs lacking the cargo-binding domain have a high activity regardless of [Ca2+] (refs 5-7). Hydrodynamic data and electron micrographs indicate that the active state is extended, whereas the inactive state is compact. Here we show the first three-dimensional structure of the myoV inactive state. Each myoV molecule consists of two heads that contain an amino-terminal motor domain followed by a lever arm that binds six calmodulins. The heads are followed by a coiled-coil dimerization domain (S2) and a carboxy-terminal globular cargo-binding domain. In the inactive structure, bending of myoV at the head-S2 junction places the cargo-binding domain near the motor domain's ATP-binding pocket, indicating that ATPase inhibition might occur through decreased rates of nucleotide exchange. The actin-binding interfaces are unobstructed, and the lever arm is oriented in a position typical of strong actin-binding states. This structure indicates that motor recycling after cargo delivery might occur through transport on actively treadmilling actin filaments rather than by diffusion. Three-dimensional structure of the myosin V inhibited state by cryoelectron tomography.,Liu J, Taylor DW, Krementsova EB, Trybus KM, Taylor KA Nature. 2006 Jul 13;442(7099):208-11. Epub 2006 Apr 16. PMID:16625208[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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