Stalk region of kinesin-related protein Unc104 has moderate ability to form coiled-coil dimer

Shimizu, Yoshikazu; Morii, Hisayuki; Arisaka, Fumio; Tanokura, Masaru

doi:10.1016/j.bbrc.2005.09.126

Cited by 12 publications

(10 citation statements)

References 24 publications

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“…These results suggest that the entire NC, as well as residues in the subsequent hinge region, are required for dimerization. This is consistent with a study of synthesized NC peptides where several residues beyond G387 were required to prevent dissociation [30]. …”

Section: Resultssupporting

confidence: 91%

“…This is consistent with studies showing coil formation by peptides corresponding to the predicted NC regions of MmKIF1A and CeUnc104 [15,30]. Importantly, we show that several residues in the hinge segment C-terminal to the NC are required for dimerization and processive motility, providing an explanation for why previous constructs that lack a full NC resulted in monomeric motors [16,28,31,36,37].…”

Section: Discussionsupporting

confidence: 92%

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Mammalian Kinesin-3 Motors Are Dimeric In Vivo and Move by Processive Motility upon Release of Autoinhibition

et al. 2009

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Kinesin-3 motors drive the transport of synaptic vesicles and other membrane-bound organelles in neuronal cells. In the absence of cargo, kinesin motors are kept inactive to prevent motility and ATP hydrolysis. Current models state that the Kinesin-3 motor KIF1A is monomeric in the inactive state and that activation results from concentration-driven dimerization on the cargo membrane. To test this model, we have examined the activity and dimerization state of KIF1A. Unexpectedly, we found that both native and expressed proteins are dimeric in the inactive state. Thus, KIF1A motors are not activated by cargo-induced dimerization. Rather, we show that KIF1A motors are autoinhibited by two distinct inhibitory mechanisms, suggesting a simple model for activation of dimeric KIF1A motors by cargo binding. Successive truncations result in monomeric and dimeric motors that can undergo one-dimensional diffusion along the microtubule lattice. However, only dimeric motors undergo ATP-dependent processive motility. Thus, KIF1A may be uniquely suited to use both diffuse and processive motility to drive long-distance transport in neuronal cells.

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Section: Resultssupporting

confidence: 91%

Section: Discussionsupporting

confidence: 92%

Mammalian Kinesin-3 Motors Are Dimeric In Vivo and Move by Processive Motility upon Release of Autoinhibition

et al. 2009

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“…This results in one-dimensional, biased Brownian diffusion along the microtubule (23). However, there is growing evidence that high local concentrations of Kinesin-3 motors lead to dimerization, causing the motors to switch from biased diffusion to more efficient processive hand-overhand walking similar to conventional kinesin (24)(25)(26)(27). Thus, it was surmised that dimerization is used as a means of regulating the transport accomplished by Kinesin-3 motors.…”

mentioning

confidence: 99%

X-ray Structure and Microtubule Interaction of the Motor Domain of Neurospora crassa NcKin3, a Kinesin with Unusual Processivity^,

et al. 2008

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Neurospora crassa kinesin NcKin3 belongs to a unique fungal-specific subgroup of small Kinesin-3-related motor proteins. One of its functions appears to be the transport of mitochondria along microtubules. Here, we present the X-ray structure of a C-terminally truncated monomeric construct of NcKin3 comprising the motor domain and the neck linker, and a 3-D image reconstruction of this motor domain bound to microtubules, by cryoelectron microscopy. The protein contains Mg‚ADP bound to the active site, yet the structure resembles an ATP-bound state. By comparison with structures of the Kinesin-3 motor Kif1A in different nucleotide states (Kikkawa, M. et al. (2001) Nature (London, U.K.) 411, 439-445), the NcKin3 structure corresponds to the AMPPCP complex of Kif1A rather than the AMPPNP complex. NcKin3-specific differences in the coordination of the nucleotide and asymmetric interactions between adjacent molecules in the crystal are discussed in the context of the unusual kinetics of the dimeric wild-type motor and the monomeric construct used for crystal structure analysis. The NcKin3 motor decorates microtubules at a stoichiometry of one head per R -tubulin heterodimer, thereby forming an axial periodicity of 8 nm. In spite of unusual extensions at the N-terminus and within flexible loops L2, L8a, and L12 (corresponding to the K-loop of monomeric kinesins), the microtubule binding geometry is similar to that of other members of the kinesin family.Kinesins form a large superfamily that comprises molecules of different architecture and function, which have in common a high-homology catalytic domain or head, which is able to bind and hydrolyze ATP 1 and to interact with microtubules in a nucleotide-dependent manner (1, 2). Most of the kinesins are motor proteins that use the energy from ATP hydrolysis for directed transport of various cellular cargoes. Conventional kinesin, the founding member of the Kinesin-1 family, is a dimeric motor protein, which moves processively along microtubules (3-5). While doing so, it hydrolyses one molecule of ATP per step in a strictly alternating way (6-10), suggesting that at any time, at least one head or motor domain is firmly attached to the microtubule. The hand-over-hand mechanism as a model of conventional kinesins processive movement is now wellsupported by single molecule microscopy techniques with nanometer resolution (11-15) and high-resolution EM of microtubule-bound motor constructs (16), although it is still a matter of debate as to how the two heads are coordinated in detail (17).Hand-over-hand walking is not the only mechanism used by kinesin motors to produce directed movement. The minus end directed C-type motor Ncd (Kinesin-14 family) seems to use a powerstroke mechanism that involves repetitive attachment and detachment of the motor (18)(19)(20). Keeping on track is not a problem for Ncd since this motor normally works in concert with many other Ncd molecules. Members of the Unc104/Kif1A family (Kinesin-3 family) are mostly monomeric, plus end directed ...

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“…Even the UNC104 motor, thought to be monomeric earlier, was also shown to dimerize at higher concentration [52]. All dimeric motors contain a flexible neck-hinge linker between the motor and coiled coil stalk.…”

Section: Discussionmentioning

confidence: 97%

Biochemical and Molecular Dynamic Simulation Analysis of a Weak Coiled Coil Association between Kinesin-II Stalks

et al. 2012

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DefinitionKinesin-2 refers to the family of motor proteins represented by conserved, heterotrimeric kinesin-II and homodimeric Osm3/Kif17 class of motors.BackgroundKinesin-II, a microtubule-based anterograde motor, is composed of three different conserved subunits, named KLP64D, KLP68D and DmKAP in Drosophila. Although previous reports indicated that coiled coil interaction between the middle segments of two dissimilar motor subunits established the heterodimer, the molecular basis of the association is still unknown.Methodology/Principal FindingsHere, we present a detailed heterodimeric association model of the KLP64D/68D stalk supported by extensive experimental analysis and molecular dynamic simulations. We find that KLP64D stalk is unstable, but forms a weak coiled coil heteroduplex with the KLP68D stalk when coexpressed in bacteria. Local instabilities, relative affinities between the C-terminal stalk segments, and dynamic long-range interactions along the stalks specify the heterodimerization. Thermal unfolding studies and independent simulations further suggest that interactions between the C-terminal stalk fragments are comparatively stable, whereas the N-terminal stalk reversibly unfolds at ambient temperature.Conclusions/SignificanceResults obtained in this study suggest that coiled coil interaction between the C-terminal stalks of kinesin-II motor subunits is held together through a few hydrophobic and charged interactions. The N-terminal stalk segments are flexible and could uncoil reversibly during a motor walk. This supports the requirement for a flexible coiled coil association between the motor subunits, and its role in motor function needs to be elucidated.

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Stalk region of kinesin-related protein Unc104 has moderate ability to form coiled-coil dimer

Cited by 12 publications

References 24 publications

Mammalian Kinesin-3 Motors Are Dimeric In Vivo and Move by Processive Motility upon Release of Autoinhibition

Mammalian Kinesin-3 Motors Are Dimeric In Vivo and Move by Processive Motility upon Release of Autoinhibition

X-ray Structure and Microtubule Interaction of the Motor Domain of Neurospora crassa NcKin3, a Kinesin with Unusual Processivity^,

Biochemical and Molecular Dynamic Simulation Analysis of a Weak Coiled Coil Association between Kinesin-II Stalks

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Stalk region of kinesin-related protein Unc104 has moderate ability to form coiled-coil dimer

Cited by 12 publications

References 24 publications

Mammalian Kinesin-3 Motors Are Dimeric In Vivo and Move by Processive Motility upon Release of Autoinhibition

Mammalian Kinesin-3 Motors Are Dimeric In Vivo and Move by Processive Motility upon Release of Autoinhibition

X-ray Structure and Microtubule Interaction of the Motor Domain of Neurospora crassa NcKin3, a Kinesin with Unusual Processivity,

Biochemical and Molecular Dynamic Simulation Analysis of a Weak Coiled Coil Association between Kinesin-II Stalks

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X-ray Structure and Microtubule Interaction of the Motor Domain of Neurospora crassa NcKin3, a Kinesin with Unusual Processivity^,