Mapping the Processivity Determinants of the Kinesin-3 Motor Domain.
Kinesin superfamily members play important roles in many diverse cellular processes, including cell motility, cell division, intracellular transport, and regulation of the microtubule cytoskeleton. How the properties of the family-defining motor domain of distinct kinesins are tailored to their different cellular roles remains largely unknown. Here, we employed molecular-dynamics simulations coupled with energetic calculations to infer the family-specific interactions of kinesin-1 and kinesin-3 motor domains with microtubules in different nucleotide states. We then used experimental mutagenesis and single-molecule motility assays to further assess the predicted residue-wise determinants of distinct kinesin-microtubule binding properties. Collectively, our results identify residues in the L8, L11, and α6 regions that contribute to family-specific microtubule interactions and whose mutation affects motor-microtubule complex stability and processive motility (the ability of an individual motor to take multiple steps along its microtubule filament). In particular, substitutions of prominent kinesin-3 residues with those found in kinesin-1, namely, R167S/H171D, K266D, and R346M, were found to decrease kinesin-3 processivity 10-fold and thus approach kinesin-1 levels.
Department of Computational Medicine and Bioinformatics, University of Michigan Medical School, Ann Arbor, Michigan.
Guido
G
Scarabelli
Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan.
Virupakshi
V
Soppina
Department of Computational Medicine and Bioinformatics, University of Michigan Medical School, Ann Arbor, Michigan.
Xin-Qiu
XQ
Yao
Institute of Structural and Molecular Biology, Birkbeck College, University of London, London, United Kingdom.
Joseph
J
Atherton
Institute of Structural and Molecular Biology, Birkbeck College, University of London, London, United Kingdom.
Carolyn A
CA
Moores
Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan. Electronic address: kjverhey@umich.edu.
Kristen J
KJ
Verhey
Department of Computational Medicine and Bioinformatics, University of Michigan Medical School, Ann Arbor, Michigan. Electronic address: bjgrant@umich.edu.
Barry J
BJ
Grant
D016547:Kinesins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism*; D056004:Molecular Dynamics Simulation; D016296:Mutagenesis; D009154:Mutation; D054730:Protein Interaction Domains and Motifs; D014404:Tubulin / Q000378:metabolism
D014404:Tubulin; D016547:Kinesins