Myosin VI undergoes cargo-mediated dimerization.
Myosin VI is the only known molecular motor that moves toward the minus ends of actin filaments; thus, it plays unique roles in diverse cellular processes. The processive walking of myosin VI on actin filaments requires dimerization of the motor, but the protein can also function as a nonprocessive monomer. The molecular mechanism governing the monomer-dimer conversion is not clear. We report the high-resolution NMR structure of the cargo-free myosin VI cargo-binding domain (CBD) and show that it is a stable monomer in solution. The myosin VI CBD binds to a fragment of the clathrin-coated vesicle adaptor Dab2 with a high affinity, and the X-ray structure of the myosin VI CBD in complex with Dab2 reveals that the motor undergoes a cargo-binding-mediated dimerization. The cargo-binding-induced dimerization may represent a general paradigm for the regulation of processivity for myosin VI as well as other myosins, including myosin VII and myosin X.
Yu
Cong
C
Department of Biochemistry, Molecular Neuroscience Center, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.
Feng
Wei
W
Wei
Zhiyi
Z
Miyanoiri
Yohei
Y
Wen
Wenyu
W
Zhao
Yanxiang
Y
Zhang
Mingjie
M
D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D051017:Apoptosis Regulatory Proteins; D022163:Clathrin-Coated Vesicles / Q000378:metabolism; D018360:Crystallography, X-Ray; D019281:Dimerization; D051379:Mice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D018995:Myosin Heavy Chains / Q000737:chemistry* / Q000378:metabolism*; D019906:Nuclear Magnetic Resonance, Biomolecular; D016415:Sequence Alignment
D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D051017:Apoptosis Regulatory Proteins; C478773:Dab2 protein, mouse; C089785:myosin VI; D018995:Myosin Heavy Chains