1
|
Shen B, Zhang Y. A mechanochemical model of the forward/backward movement of motor protein kinesin-1. J Biol Chem 2022; 298:101948. [PMID: 35447112 PMCID: PMC9117889 DOI: 10.1016/j.jbc.2022.101948] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 04/11/2022] [Accepted: 04/14/2022] [Indexed: 11/25/2022] Open
Abstract
Kinesin-1 is an ATP-driven, two-headed motor protein that transports intracellular cargoes (loads) along microtubules. The movement of kinesin-1 has generally been modeled according to its correlation with ATP cleavage (forward movement), synthesis (backward movement), or unproductive cleavage (futile consumption). Based on recent experimental observations, we formulate a mechanochemical model for this movement in which the forward/backward/futile cycle can be realized through multiple biochemical pathways. Our results show that the backward motion of kinesin-1 occurs mainly through backward sliding along the microtubule and is usually also coupled with ATP hydrolysis. We also found that with a low external load, about 80% of ATP is wasted (futile consumption) by kinesin-1. Furthermore, at high ATP concentrations or under high external loads, both heads of kinesin-1 are always in the ATP- or ADP ⋅ Pi-binding state and tightly bound to the microtubule, while at low ATP concentrations and low loads, kinesin-1 is mainly in the one-head-bound state. Unless the external load is near the stall force, the motion of kinesin-1 is almost deterministic.
Collapse
Affiliation(s)
- Beibei Shen
- Shanghai Key Laboratory for Contemporary Applied Mathematics, School of Mathematical Sciences, Fudan University, Shanghai 200433, China
| | - Yunxin Zhang
- Shanghai Key Laboratory for Contemporary Applied Mathematics, School of Mathematical Sciences, Fudan University, Shanghai 200433, China.
| |
Collapse
|
2
|
Stepp WL, Ökten Z. Resolving kinesin stepping: one head at a time. Life Sci Alliance 2019; 2:2/5/e201900456. [PMID: 31601622 PMCID: PMC6788457 DOI: 10.26508/lsa.201900456] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 09/27/2019] [Accepted: 09/27/2019] [Indexed: 11/24/2022] Open
Abstract
Kinesins are well known to power diverse long-range transport processes in virtually all eukaryotic cells. The ATP-dependent processive stepping as well as the regulation of kinesin' activity have, thus, been the focus of extensive studies over the past decades. It is widely accepted that kinesin motors can self-regulate their activity by suppressing the catalytic activity of the "heads." The distal random coil at the C terminus, termed "tail domain," is proposed to mediate this autoinhibition; however, a direct regulatory influence of the tail on the processive stepping of kinesin proved difficult to capture. Here, we simultaneously tracked the two distinct head domains in the kinesin-2 motor using dual-color super resolution microscopy (dcFIONA) and reveal for the first time their individual properties during processive stepping. We show that the autoinhibitory wild-type conformation selectively impacts one head in the heterodimer but not the other. Our results provide insights into the regulated kinesin stepping that had escaped experimental scrutiny so far.
Collapse
Affiliation(s)
- Willi L Stepp
- Physik Department E22, Technische Universität München, Garching, Germany
| | - Zeynep Ökten
- Physik Department E22, Technische Universität München, Garching, Germany .,Munich Center for Integrated Protein Science, Munich, Germany
| |
Collapse
|
3
|
Structural basis of small molecule ATPase inhibition of a human mitotic kinesin motor protein. Sci Rep 2017; 7:15121. [PMID: 29123223 PMCID: PMC5680195 DOI: 10.1038/s41598-017-14754-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 10/13/2017] [Indexed: 11/08/2022] Open
Abstract
Kinesin microtubule motor proteins play essential roles in division, including attaching chromosomes to spindles and crosslinking microtubules for spindle assembly. Human kinesin-14 KIFC1 is unique in that cancer cells with amplified centrosomes are dependent on the motor for viable division because of its ability to cluster centrosomes and form bipolar spindles, but it is not required for division in almost all normal cells. Screens for small molecule inhibitors of KIFC1 have yielded several candidates for further development, but obtaining structural data to determine their sites of binding has been difficult. Here we compare a previously unreported KIFC1 crystal structure with new structures of two closely related kinesin-14 proteins, Ncd and KIFC3, to determine the potential binding site of a known KIFC1 ATPase inhibitor, AZ82. We analyze the previously identified kinesin inhibitor binding sites and identify features of AZ82 that favor binding to one of the sites, the α4/α6 site. This selectivity can be explained by unique structural features of the KIFC1 α4/α6 binding site. These features may help improve the drug-like properties of AZ82 and other specific KIFC1 inhibitors.
Collapse
|
4
|
Allocating dissipation across a molecular machine cycle to maximize flux. Proc Natl Acad Sci U S A 2017; 114:11057-11062. [PMID: 29073016 DOI: 10.1073/pnas.1707534114] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Biomolecular machines consume free energy to break symmetry and make directed progress. Nonequilibrium ATP concentrations are the typical free energy source, with one cycle of a molecular machine consuming a certain number of ATP, providing a fixed free energy budget. Since evolution is expected to favor rapid-turnover machines that operate efficiently, we investigate how this free energy budget can be allocated to maximize flux. Unconstrained optimization eliminates intermediate metastable states, indicating that flux is enhanced in molecular machines with fewer states. When maintaining a set number of states, we show that-in contrast to previous findings-the flux-maximizing allocation of dissipation is not even. This result is consistent with the coexistence of both "irreversible" and reversible transitions in molecular machine models that successfully describe experimental data, which suggests that, in evolved machines, different transitions differ significantly in their dissipation.
Collapse
|
5
|
Kinesin rotates unidirectionally and generates torque while walking on microtubules. Proc Natl Acad Sci U S A 2017; 114:10894-10899. [PMID: 28973906 DOI: 10.1073/pnas.1706985114] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Cytoskeletal motors drive many essential cellular processes. For example, kinesin-1 transports cargo in a step-wise manner along microtubules. To resolve rotations during stepping, we used optical tweezers combined with an optical microprotractor and torsion balance using highly birefringent microspheres to directly and simultaneously measure the translocation, rotation, force, and torque generated by individual kinesin-1 motors. While, at low adenosine 5'-triphosphate (ATP) concentrations, motors did not generate torque, we found that motors translocating along microtubules at saturating ATP concentrations rotated unidirectionally, producing significant torque on the probes. Accounting for the rotational work makes kinesin a highly efficient machine. These results imply that the motor's gait follows a rotary hand-over-hand mechanism. Our method is generally applicable to study rotational and linear motion of molecular machines, and our findings have implications for kinesin-driven cellular processes.
Collapse
|
6
|
Guo SK, Wang PY, Xie P. Dynamics of dimeric kinesins: Limping, effect of longitudinal force, effects of neck linker extension and mutation, and comparison between kinesin-1 and kinesin-2. Int J Biol Macromol 2017; 105:1126-1137. [PMID: 28754624 DOI: 10.1016/j.ijbiomac.2017.07.147] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 07/18/2017] [Accepted: 07/24/2017] [Indexed: 10/19/2022]
Abstract
Conventional kinesin (kinesin-1) can walk on microtubule filaments in an asymmetric hand-over-hand manner, exhibiting a marked alternation in the mean dwell time in successive steps. Here, we study computationally the asymmetric stepping dynamics of the kinesin-1 homodimer, revealing its origin and providing quantitative explanations of the available experimental data. The alternation in the mean dwell time in successive steps arises from the alternation in the mechanochemical coupling ratio, which is in turn caused by the alternation in the slight variation of the stretched neck linker length. Both the vertical and backward longitudinal forces can enhance the asymmetric ratio. Additionally, other aspects of the stepping dynamics of the dimer such as the velocity versus longitudinal force, extended neck linker, etc., are also studied. In particular, the conflicting experimental data, with some showing that the velocity does not change with the forward longitudinal load while others showing that the velocity increases largely with the forward longitudinal load, are explained quantitatively and consistently. The intriguing experimental data showing that cysteine-light Drosophila and human kinesin-1 mutants have different load-dependent velocity from the wild-type cases as well as that kinesin-2 dimers have different load-dependent velocity from the kinesin-1 are also explained consistently and quantitatively.
Collapse
Affiliation(s)
- Si-Kao Guo
- Key Laboratory of Soft Matter Physics and Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Peng-Ye Wang
- Key Laboratory of Soft Matter Physics and Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Ping Xie
- Key Laboratory of Soft Matter Physics and Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
| |
Collapse
|
7
|
The structural switch of nucleotide-free kinesin. Sci Rep 2017; 7:42558. [PMID: 28195215 PMCID: PMC5307337 DOI: 10.1038/srep42558] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 01/10/2017] [Indexed: 11/18/2022] Open
Abstract
Kinesin-1 is an ATP-dependent motor protein that moves towards microtubules (+)-ends. Whereas structures of isolated ADP-kinesin and of complexes with tubulin of apo-kinesin and of ATP-like-kinesin are available, structural data on apo-kinesin-1 in the absence of tubulin are still missing, leaving the role of nucleotide release in the structural cycle unsettled. Here, we identified mutations in the kinesin nucleotide-binding P-loop motif that interfere with ADP binding. These mutations destabilize the P-loop (T87A mutant) or magnesium binding (T92V), highlighting a dual mechanism for nucleotide release. The structures of these mutants in their apo form are either isomorphous to ADP-kinesin-1 or to tubulin-bound apo-kinesin-1. Remarkably, both structures are also obtained from the nucleotide-depleted wild-type protein. Our results lead to a model in which, when detached from microtubules, apo-kinesin possibly occupies the two conformations we characterized, whereas, upon microtubule binding, ADP-kinesin converts to the tubulin-bound apo-kinesin conformation and releases ADP. This conformation is primed to bind ATP and, therefore, to run through the natural nucleotide cycle of kinesin-1.
Collapse
|
8
|
Cochran JC. Kinesin Motor Enzymology: Chemistry, Structure, and Physics of Nanoscale Molecular Machines. Biophys Rev 2015; 7:269-299. [PMID: 28510227 DOI: 10.1007/s12551-014-0150-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Accepted: 11/16/2014] [Indexed: 11/25/2022] Open
Abstract
Molecular motors are enzymes that convert chemical potential energy into controlled kinetic energy for mechanical work inside cells. Understanding the biophysics of these motors is essential for appreciating life as well as apprehending diseases that arise from motor malfunction. This review focuses on kinesin motor enzymology with special emphasis on the literature that reports the chemistry, structure and physics of several different kinesin superfamily members.
Collapse
Affiliation(s)
- J C Cochran
- Department of Molecular & Cellular Biochemistry, Indiana University, Simon Hall Room 405C, 212 S. Hawthorne Dr., Bloomington, IN, 47405, USA.
| |
Collapse
|
9
|
Rank KC, Rayment I. Functional asymmetry in kinesin and dynein dimers. Biol Cell 2012; 105:1-13. [PMID: 23066835 DOI: 10.1111/boc.201200044] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Accepted: 10/08/2012] [Indexed: 11/28/2022]
Abstract
Active transport along the microtubule lattice is a complex process that involves both the Kinesin and Dynein superfamily of motors. Transportation requires sophisticated regulation much of which occurs through the motor's tail domain. However, a significant portion of this regulation also occurs through structural changes that arise in the motor and the microtubule upon binding. The most obvious structural change being the manifestation of asymmetry. To a first approximation in solution, kinesin dimers exhibit twofold symmetry, and microtubules exhibit helical symmetry. The higher symmetries of both the kinesin dimers and microtubule lattice are lost on formation of the kinesin-microtubule complex. Loss of symmetry has functional consequences such as an asymmetric hand-over-hand mechanism in plus-end-directed kinesins, asymmetric microtubule binding in the Kinesin-14 family, spatially biased stepping in dynein and cooperative binding of additional motors to the microtubule. This review focusses on how the consequences of asymmetry affect regulation of motor heads within a dimer, dimers within an ensemble of motors, and suggests how these asymmetries may affect regulation of active transport within the cell.
Collapse
Affiliation(s)
- Katherine C Rank
- Department of Biochemistry, University of Wisconsin, Madison, WI 53706, USA
| | | |
Collapse
|
10
|
Altered nucleotide-microtubule coupling and increased mechanical output by a kinesin mutant. PLoS One 2012; 7:e47148. [PMID: 23077560 PMCID: PMC3473065 DOI: 10.1371/journal.pone.0047148] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Accepted: 09/12/2012] [Indexed: 11/19/2022] Open
Abstract
Kinesin motors hydrolyze ATP to produce force and do work in the cell – how the motors do this is not fully understood, but is thought to depend on the coupling of ATP hydrolysis to microtubule binding by the motor. Transmittal of conformational changes from the microtubule- to the nucleotide-binding site has been proposed to involve the central β-sheet, which could undergo large structural changes important for force production. We show here that mutation of an invariant residue in loop L7 of the central β-sheet of the Drosophila kinesin-14 Ncd motor alters both nucleotide and microtubule binding, although the mutated residue is not present in either site. Mutants show weak-ADP/tight-microtubule binding, instead of tight-ADP/weak-microtubule binding like wild type – they hydrolyze ATP faster than wild type, move faster in motility assays, and assemble long spindles with greatly elongated poles, which are also produced by simulations of assembly with tighter microtubule binding and faster sliding. The mutated residue acts like a mechanochemical coupling element – it transmits changes between the microtubule-binding and active sites, and can switch the state of the motor, increasing mechanical output by the motor. One possibility, based on our findings, is that movements by the residue and the loop that contains it could bend or distort the central β-sheet, mediating free energy changes that lead to force production.
Collapse
|
11
|
Hallen MA, Liang ZY, Endow SA. Two-state displacement by the kinesin-14 Ncd stalk. Biophys Chem 2011; 154:56-65. [PMID: 21288629 DOI: 10.1016/j.bpc.2011.01.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2010] [Revised: 01/03/2011] [Accepted: 01/03/2011] [Indexed: 11/25/2022]
Abstract
The nonprocessive kinesin-14 Ncd motor binds to microtubules and hydrolyzes ATP, undergoing a single displacement before releasing the microtubule. A lever-like rotation of the coiled-coil stalk is thought to drive Ncd displacements or steps along microtubules. Crystal structures and cryoelectron microscopy reconstructions imply that stalk rotation is correlated with ADP release and microtubule binding by the motor. Here we report FRET assays showing that the end of the stalk is more than ~9nm from the microtubule when wild-type Ncd binds microtubules without added nucleotide, but the stalk is within ~6nm of the microtubule surface when the microtubule-bound motor binds an ATP analogue, matching the rotated state observed in crystal structures. We propose that the stalk rotation is initiated when the motor binds to microtubules and releases ADP, and is completed when ATP binds.
Collapse
Affiliation(s)
- Mark A Hallen
- Department of Cell Biology, Structural Biology & Biophysics Program, Duke University Medical Center, Durham, NC 27710, USA.
| | | | | |
Collapse
|
12
|
Xie P. Mechanism of processive movement of monomeric and dimeric kinesin molecules. Int J Biol Sci 2010; 6:665-74. [PMID: 21060728 PMCID: PMC2974169 DOI: 10.7150/ijbs.6.665] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Accepted: 10/19/2010] [Indexed: 11/05/2022] Open
Abstract
Kinesin molecules are motor proteins capable of moving along microtubule by hydrolyzing ATP. They generally have several forms of construct. This review focuses on two of the most studied forms: monomers such as KIF1A (kinesin-3 family) and dimers such as conventional kinesin (kinesin-1 family), both of which can move processively towards the microtubule plus end. There now exist numerous models that try to explain how the kinesin molecules convert the chemical energy of ATP hydrolysis into the mechanical energy to "power" their processive movement along microtubule. Here, we attempt to present a comprehensive review of these models. We further propose a new hybrid model for the dimeric kinesin by combining the existing models and provide a framework for future studies in this subject.
Collapse
Affiliation(s)
- Ping Xie
- Key Laboratory of Soft Matter Physics and Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| |
Collapse
|
13
|
Affiliation(s)
- Sharyn A Endow
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA.
| | | | | |
Collapse
|
14
|
Heuston E, Bronner CE, Kull FJ, Endow SA. A kinesin motor in a force-producing conformation. BMC STRUCTURAL BIOLOGY 2010; 10:19. [PMID: 20602775 PMCID: PMC2906495 DOI: 10.1186/1472-6807-10-19] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2010] [Accepted: 07/05/2010] [Indexed: 11/26/2022]
Abstract
Background Kinesin motors hydrolyze ATP to produce force and move along microtubules, converting chemical energy into work by a mechanism that is only poorly understood. Key transitions and intermediate states in the process are still structurally uncharacterized, and remain outstanding questions in the field. Perturbing the motor by introducing point mutations could stabilize transitional or unstable states, providing critical information about these rarer states. Results Here we show that mutation of a single residue in the kinesin-14 Ncd causes the motor to release ADP and hydrolyze ATP faster than wild type, but move more slowly along microtubules in gliding assays, uncoupling nucleotide hydrolysis from force generation. A crystal structure of the motor shows a large rotation of the stalk, a conformation representing a force-producing stroke of Ncd. Three C-terminal residues of Ncd, visible for the first time, interact with the central β-sheet and dock onto the motor core, forming a structure resembling the kinesin-1 neck linker, which has been proposed to be the primary force-generating mechanical element of kinesin-1. Conclusions Force generation by minus-end Ncd involves docking of the C-terminus, which forms a structure resembling the kinesin-1 neck linker. The mechanism by which the plus- and minus-end motors produce force to move to opposite ends of the microtubule appears to involve the same conformational changes, but distinct structural linkers. Unstable ADP binding may destabilize the motor-ADP state, triggering Ncd stalk rotation and C-terminus docking, producing a working stroke of the motor.
Collapse
|
15
|
FRET measurements of kinesin neck orientation reveal a structural basis for processivity and asymmetry. Proc Natl Acad Sci U S A 2010; 107:5453-8. [PMID: 20212149 DOI: 10.1073/pnas.0914924107] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
As the smallest and simplest motor enzymes, kinesins have served as the prototype for understanding the relationship between protein structure and mechanochemical function of enzymes in this class. Conventional kinesin (kinesin-1) is a motor enzyme that transports cargo toward the plus end of microtubules by a processive, asymmetric hand-over-hand mechanism. The coiled-coil neck domain, which connects the two kinesin motor domains, contributes to kinesin processivity (the ability to take many steps in a row) and is proposed to be a key determinant of the asymmetry in the kinesin mechanism. While previous studies have defined the orientation and position of microtubule-bound kinesin motor domains, the disposition of the neck coiled-coil remains uncertain. We determined the neck coiled-coil orientation using a multidonor fluorescence resonance energy transfer (FRET) technique to measure distances between microtubules and bound kinesin molecules. Microtubules were labeled with a new fluorescent taxol donor, TAMRA-X-taxol, and kinesin derivatives with an acceptor fluorophore attached at positions on the motor and neck coiled-coil domains were used to reconstruct the positions and orientations of the domains. FRET measurements to positions on the motor domain were largely consistent with the domain orientation determined in previous studies, validating the technique. Measurements to positions on the neck coiled-coil were inconsistent with a radial orientation and instead demonstrated that the neck coiled-coil is parallel to the microtubule surface. The measured orientation provides a structural explanation for how neck surface residues enhance processivity and suggests a simple hypothesis for the origin of kinesin step asymmetry and "limping."
Collapse
|
16
|
Fehr AN, Gutiérrez-Medina B, Asbury CL, Block SM. On the origin of kinesin limping. Biophys J 2009; 97:1663-70. [PMID: 19751671 DOI: 10.1016/j.bpj.2009.07.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2009] [Revised: 07/06/2009] [Accepted: 07/09/2009] [Indexed: 10/20/2022] Open
Abstract
Kinesin is a dimeric motor with twin catalytic heads joined to a common stalk. Kinesin molecules move processively along microtubules in a hand-over-hand walk, with the two heads advancing alternately. Recombinant kinesin constructs with short stalks have been found to "limp", i.e., exhibit alternation in the dwell times of successive steps. Limping behavior implies that the molecular rearrangements underlying even- and odd-numbered steps must differ, but the mechanism by which such rearrangements lead to limping remains unsolved. Here, we used an optical force clamp to measure individual, recombinant dimers and test candidate explanations for limping. Introducing a covalent cross-link into the stalk region near the heads had no effect on limping, ruling out possible stalk misregistration during coiled-coil formation as a cause. Limping was equally unaffected by mutations that produced 50-fold changes in stalk stiffness, ruling out models where limping arises from an asymmetry in torsional strain. However, limping was enhanced by perturbations that increased the vertical component of load on the motor, including increases in bead size or net load, and decreases in the stalk length. These results suggest that kinesin heads take different vertical trajectories during alternate steps, and that the rates for these motions are differentially sensitive to load.
Collapse
Affiliation(s)
- Adrian N Fehr
- Department of Applied Physics, Stanford University, Stanford, California, USA
| | | | | | | |
Collapse
|
17
|
Thoresen T, Gelles J. Processive movement by a kinesin heterodimer with an inactivating mutation in one head. Biochemistry 2008; 47:9514-21. [PMID: 18702529 PMCID: PMC2586147 DOI: 10.1021/bi800747e] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A single molecule of the motor enzyme kinesin-1 keeps a tight grip on its microtubule track, making tens or hundreds of discrete, unidirectional 8 nm steps before dissociating. This high duty ratio processive movement is thought to require a mechanism in which alternating stepping of the two head domains of the kinesin dimer is driven by alternating, overlapped cycles of ATP hydrolysis by the two heads. The R210K point mutation in Drosophila kinesin heavy chain was reported to disrupt the ability of the enzyme active site to catalyze ATP P-O bond cleavage. We expressed R210K homodimers as well as isolated R210K heads and confirmed that both are essentially inactive. We then coexpressed tagged R210K subunits with untagged wild-type subunits and affinity purified R210K/wild-type heterodimers together with the inactive R210K homodimers. In contrast to the R210K head or homodimer, the heterodimer was a highly active (>50% of wild-type) microtubule-stimulated ATPase, and the heterodimer displayed high duty ratio processive movement in single-molecule motility experiments. Thus, dimerization of a subunit containing the inactivating mutation with a functional subunit can complement the mutation; this must occur either by lowering or by bypassing kinetic barriers in the ATPase or mechanical cycles of the mutant head. The observations provide support for kinesin-1 gating mechanisms in which one head stimulates the rate of essential processes in the other.
Collapse
Affiliation(s)
- Todd Thoresen
- Biochemistry Department and Biophysics & Structural Biology Graduate Program, Brandeis University, Waltham, Massachusetts 02454-9110, USA
| | | |
Collapse
|
18
|
Kikkawa M. The role of microtubules in processive kinesin movement. Trends Cell Biol 2008; 18:128-35. [PMID: 18280159 DOI: 10.1016/j.tcb.2008.01.002] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2007] [Revised: 01/04/2008] [Accepted: 01/07/2008] [Indexed: 10/22/2022]
Abstract
Kinesins are microtubule-based motors that are important for various intracellular transport processes. To understand the mechanism of kinesin movement, X-ray crystallography has been used to study the atomic structures of kinesin. However, as crystal structures of kinesin alone accumulate, it is becoming clear that kinesin structures should also be investigated with the microtubule to understand the contribution of the microtubule track to the nucleotide-induced conformational changes of kinesin. Recently, several high-resolution structures of kinesin with microtubules were obtained using cryo-electron microscopy. Comparison with X-ray crystallographic structures revealed the importance of the microtubule in determining the conformation of kinesin. Together with recent biophysical data, we describe different structural models of processive kinesin movement and provide a framework for future experiments.
Collapse
Affiliation(s)
- Masahide Kikkawa
- Graduate School of Science, Kyoto University, Oiwake, Kita-shirakawa, Sakyo-ku, Kyoto, 606-8502, Japan.
| |
Collapse
|
19
|
Marx A, Müller J, Mandelkow EM, Woehlke G, Bouchet-Marquis C, Hoenger A, Mandelkow E. X-ray Structure and Microtubule Interaction of the Motor Domain of Neurospora crassa NcKin3, a Kinesin with Unusual Processivity,. Biochemistry 2008; 47:1848-61. [DOI: 10.1021/bi701483h] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Alexander Marx
- Max-Planck-Unit for Structural Molecular Biology, Notkestrasse 85, 22607 Hamburg, Germany, Institute for Cell Biology, Ludwig-Maximilians-University Munich, Schillerstrasse 42, 80336, Germany, and Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309-0347
| | - Jens Müller
- Max-Planck-Unit for Structural Molecular Biology, Notkestrasse 85, 22607 Hamburg, Germany, Institute for Cell Biology, Ludwig-Maximilians-University Munich, Schillerstrasse 42, 80336, Germany, and Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309-0347
| | - Eva-Maria Mandelkow
- Max-Planck-Unit for Structural Molecular Biology, Notkestrasse 85, 22607 Hamburg, Germany, Institute for Cell Biology, Ludwig-Maximilians-University Munich, Schillerstrasse 42, 80336, Germany, and Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309-0347
| | - Günther Woehlke
- Max-Planck-Unit for Structural Molecular Biology, Notkestrasse 85, 22607 Hamburg, Germany, Institute for Cell Biology, Ludwig-Maximilians-University Munich, Schillerstrasse 42, 80336, Germany, and Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309-0347
| | - Cedric Bouchet-Marquis
- Max-Planck-Unit for Structural Molecular Biology, Notkestrasse 85, 22607 Hamburg, Germany, Institute for Cell Biology, Ludwig-Maximilians-University Munich, Schillerstrasse 42, 80336, Germany, and Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309-0347
| | - Andreas Hoenger
- Max-Planck-Unit for Structural Molecular Biology, Notkestrasse 85, 22607 Hamburg, Germany, Institute for Cell Biology, Ludwig-Maximilians-University Munich, Schillerstrasse 42, 80336, Germany, and Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309-0347
| | - Eckhard Mandelkow
- Max-Planck-Unit for Structural Molecular Biology, Notkestrasse 85, 22607 Hamburg, Germany, Institute for Cell Biology, Ludwig-Maximilians-University Munich, Schillerstrasse 42, 80336, Germany, and Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309-0347
| |
Collapse
|
20
|
Xie P, Dou SX, Wang PY. Processivity of single-headed kinesin motors. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2007; 1767:1418-27. [PMID: 17976515 DOI: 10.1016/j.bbabio.2007.09.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2007] [Revised: 08/13/2007] [Accepted: 09/20/2007] [Indexed: 11/18/2022]
Abstract
The processive movement of single-headed kinesins is studied by using a ratchet model of non-Markov process, which is built on the experimental evidence that the strong binding of kinesin to microtubule in rigor state induces a large apparent change in the local microtubule conformation. In the model, the microtubule plays a crucial active role in the kinesin movement, in contrast to the previous belief that the microtubule only acts as a passive track for the kinesin motility. The unidirectional movement of single-headed kinesin is resulted from the asymmetric periodic potential between kinesin and microtubule while its processivity is determined by its binding affinity for microtubule in the weak ADP state. Using the model, various experimental results for monomeric kinesin KIF1A, such as the mean step size, the step-size distribution, the long run length and the mean velocity versus load, can be well explained quantitatively. This local conformational change of the microtubule may also play important roles in the processive movement of conventional two-headed kinesins. An experiment to verify the model is suggested.
Collapse
Affiliation(s)
- Ping Xie
- Department of Physics, Renmin University of China, Beijing 100872, China.
| | | | | |
Collapse
|
21
|
Abstract
Several lines of experimental evidence suggest that the conventional kinesin 1 walks by an asymmetric hand-over-hand mechanism, although it is a homodimer. In the previous study, we examined several important force-dependent features of the hand-over-hand mechanism of kinesin. In this study, we focus on the asymmetry in the hand-over-hand mechanism. We show that the experimentally observed kinesin limping can be explained in our model by the variation of the neck linker lengths in the kinesin stepping (which has also been suggested earlier by others). We also study the experimentally observed processive motion of a mutant heterodimer of kinesin, in which only one of the two heads has the capability of ATP hydrolysis, as well as the walking of wild-type kinesin in the presence of both ATP and its analogue AMPPNP. We show that the possible processive walking of the heterodimeric kinesin can be explained by introducing a force-generating intermediate, the kinesin-ATP complex, which is different from the posthydrolytic species, kinesin-ADP/Pi.
Collapse
Affiliation(s)
- Qiang Shao
- Department of Chemistry, Texas A&M University, College Station, Texas 77845, USA
| | | |
Collapse
|
22
|
Skowronek KJ, Kocik E, Kasprzak AA. Subunits interactions in kinesin motors. Eur J Cell Biol 2007; 86:559-68. [PMID: 17628208 DOI: 10.1016/j.ejcb.2007.05.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2007] [Revised: 05/21/2007] [Accepted: 05/29/2007] [Indexed: 12/30/2022] Open
Abstract
Kinesins form a large and diverse superfamily of proteins involved in numerous important cellular processes. The majority of them are molecular motors moving along microtubules. Conversion of chemical energy into mechanical work is accomplished in a sequence of events involving both biochemical and conformational alternation of the motor structure called the mechanochemical cycle. Different members of the kinesin superfamily can either perform their function in large groups or act as single molecules. Conventional kinesin, a member of the kinesin-1 subfamily, exemplifies the second type of motor which requires tight coordination of the mechanochemical cycle in two identical subunits to accomplish processive movement toward the microtubule plus end. Recent results strongly support an asymmetric hand-over-hand model of "walking" for this protein. Conformational strain between two subunits at the stage of the cycle where both heads are attached to the microtubule seems to be a major factor in intersubunit coordination, although molecular and kinetic details of this phenomenon are not yet deciphered. We discuss also current knowledge concerning intersubunit coordination in other kinesin subfamilies. Members of the kinesin-3 class use at least three different mechanisms of movement and can translocate in monomeric or dimeric forms. It is not known to what extent intersubunit coordination takes place in Ncd, a dimeric member of the kinesin-14 subfamily which, unlike conventional kinesin, exercises a power-stroke toward the microtubule minus end. Eg5, a member of the kinesin-5 subfamily is a homotetrameric protein with two kinesin-1-like dimeric halves controlled by their relative orientation on two microtubules. It seems that diversity of subunit organization, quaternary structures and cellular functions in the kinesin superfamily are reflected also by the divergent extent and mechanism of intersubunit coordination during kinesin movement along microtubules.
Collapse
Affiliation(s)
- Krzysztof J Skowronek
- Motor Proteins Laboratory, Department of Biochemistry, Nencki Institute of Experimental Biology, 3 Pasteur Street, 02-093 Warsaw, Poland
| | | | | |
Collapse
|
23
|
Xie P, Dou SX, Wang PY. Limping of Homodimeric Kinesin Motors. J Mol Biol 2007; 366:976-85. [PMID: 17188298 DOI: 10.1016/j.jmb.2006.10.081] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2006] [Revised: 09/30/2006] [Accepted: 10/04/2006] [Indexed: 11/16/2022]
Abstract
Conventional kinesin, a homodimeric motor protein that transports cargo in various cells, walks limpingly along microtubule. Here, based on our previously proposed partially coordinated hand-over-hand model, we present a new mechanism for the limping behaviors of both wild-type and mutant kinesin homodimers. The limping is caused by different vertical forces acting on the heads in two successive steps during the processive movement of the dimer. From the model, various theoretical results, such as the dependences of the mean dwell time and dwell time ratio on the coiled-coil length and on the external load as well as the effect of vertical force on velocity, are in good agreement with previous experimental results. We predict that a high degree of limping will correlate strongly with a high sensitivity of ATP turnover rate to upwards force.
Collapse
Affiliation(s)
- Ping Xie
- Laboratory of Soft Matter Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China.
| | | | | |
Collapse
|
24
|
Tomishige M, Stuurman N, Vale RD. Single-molecule observations of neck linker conformational changes in the kinesin motor protein. Nat Struct Mol Biol 2006; 13:887-94. [PMID: 17013387 DOI: 10.1038/nsmb1151] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2006] [Accepted: 09/05/2006] [Indexed: 11/08/2022]
Abstract
Kinesin-1 is a dimeric motor protein that moves cargo processively along microtubules. Kinesin motility has been proposed to be driven by the coordinated forward extension of the neck linker (a approximately 12-residue peptide) in one motor domain and the rearward positioning of the neck linker in the partner motor domain. To test this model, we have introduced fluorescent dyes selectively into one subunit of the kinesin dimer and performed 'half-molecule' fluorescence resonance energy transfer to measure conformational changes of the neck linker. We show that when kinesin binds with both heads to the microtubule, the neck linkers in the rear and forward heads extend forward and backward, respectively. During ATP-driven motility, the neck linkers switch between these conformational states. These results support the notion that neck linker movements accompany the 'hand-over-hand' motion of the two motor domains.
Collapse
Affiliation(s)
- Michio Tomishige
- Department of Applied Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
| | | | | |
Collapse
|
25
|
Kikkawa M, Hirokawa N. High-resolution cryo-EM maps show the nucleotide binding pocket of KIF1A in open and closed conformations. EMBO J 2006; 25:4187-94. [PMID: 16946706 PMCID: PMC1570440 DOI: 10.1038/sj.emboj.7601299] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2006] [Accepted: 08/01/2006] [Indexed: 11/08/2022] Open
Abstract
Kinesin is an ATP-driven microtubule (MT)-based motor fundamental to organelle transport. Although a number of kinesin crystal structures have been solved, the structural evidence for coupling between the bound nucleotide and the conformation of kinesin is elusive. In addition, the structural basis of the MT-induced ATPase activity of kinesin is not clear because of the absence of the MT in the structure. Here, we report cryo-electron microscopy structures of the monomeric kinesin KIF1A-MT complex in two nucleotide states at about 10 A resolution, sufficient to reveal the secondary structure. These high-resolution maps visualized clear structural changes that suggest a mechanical pathway from the nucleotide to the neck linker via the motor core rotation. In addition, new nucleotide binding pocket conformations are observed that are different from X-ray crystallographic structures; it is closed in the 5'-adenylyl-imidodiphosphate state, but open in the ADP state. These results suggest a structural model of biased diffusion movement of monomeric kinesin motor.
Collapse
Affiliation(s)
- Masahide Kikkawa
- Department of Cell Biology, Southwestern Medical Center, University of Texas, Dallas, TX, USA
| | - Nobutaka Hirokawa
- Department of Cell Biology and Anatomy, Graduate School of Medicine Hongo, University of Tokyo, Bunkyo-ku, Tokyo, Japan
- Department of Cell Biology and Anatomy, University of Tokyo, Graduate School of Medicine, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan. Tel.: +81 3 5841 3326; Fax: +81 3 5802 8646; E-mail:
| |
Collapse
|
26
|
Abstract
We present here a simple theoretical model for conventional kinesin. The model reproduces the hand-over-hand mechanism for kinesin walking to the plus end of a microtubule. A large hindering force induces kinesin to walk slowly to the minus end, again by a hand-over-hand mechanism. Good agreement is obtained between the calculated and experimental results on the external force dependence of the walking speed, the forward/backward step ratio, and dwell times for both forward and backward steps. The model predicts that both forward and backward motions of kinesin take place at the same chemical state of the motor heads, with the front head being occupied by an ATP (or ADP,Pi) and the rear being occupied by an ADP. The direction of motion is a result of the competition between the power stroke produced by the front head and the external load. The other predictions include the external force dependence of the chemomechanical coupling ratio (e.g., the stepping distance/ATP ratio) and the walking speed of kinesin at force ranges that have not been tested by experiments. The model predicts that the chemomechanical coupling remains tight in a large force range. However, when the external force is very large (e.g., approximately 18 pN), kinesin slides in an inchworm fashion, and the translocation of kinesin becomes loosely coupled to ATP turnovers.
Collapse
Affiliation(s)
- Qiang Shao
- Department of Chemistry, Texas A&M University, College Station, TX 77843
| | - Yi Qin Gao
- Department of Chemistry, Texas A&M University, College Station, TX 77843
- *To whom correspondence should be addressed. E-mail:
| |
Collapse
|
27
|
Xie P, Dou SX, Wang PY. Mechanochemical couplings of kinesin motors. Biophys Chem 2006; 123:58-76. [PMID: 16707205 DOI: 10.1016/j.bpc.2006.04.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2006] [Revised: 04/03/2006] [Accepted: 04/08/2006] [Indexed: 11/26/2022]
Abstract
Kinesins are molecular motors capable of moving processively along microtubule in a stepwise manner by hydrolyzing ATP. Numerous experimental results on various aspects of their dynamical behaviours are available in literature. Although a number of models of tightly coordinated mechanism have been proposed to explain some experimental results, up to now no good explanation has been given to all these experimental results by using a single model. We have recently proposed such a model of partially coordinated hand-over-hand moving mechanism. In this paper, we use this model to study in detail various aspects of the dynamical properties of single kinesin molecules. We show that kinesin dimers walk hand-over-hand along microtubules in a partially coordinated rather than a tightly coordinated manner. The degree of coordination depends on the ratio of the two heads' ATPase rates that are in turn determined by both internal elastic force and external load. We have tested this model using various available experimental results on different samples and obtained a good agreement between the theory and the experiments.
Collapse
Affiliation(s)
- Ping Xie
- Laboratory of Soft Matter Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China.
| | | | | |
Collapse
|
28
|
Xie P, Dou SX, Wang PY. Model for kinetics of wild-type and mutant kinesins. Biosystems 2006; 84:24-38. [PMID: 16378677 DOI: 10.1016/j.biosystems.2005.09.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2005] [Revised: 09/30/2005] [Accepted: 09/30/2005] [Indexed: 11/21/2022]
Abstract
A hand-over-hand model is presented for the processive movement of two-headed kinesin based on previous structural and biochemical studies. In the model, the ATPase activities of the two heads are regulated by forces, both from internal elasticity and external load, exerted on their neck linkers. The results from the model show that the two heads may be partially coordinated in their ATPase cycles: in the case of backward load or low forward load, the ATPase cycles of its two heads are well coordinated, whereas in the case of high forward load, they are no longer well coordinated. The model gives results that show good quantitative agreement with both previous biochemical and mechanical experimental results such as the limping of homodimers and the dependences of mean velocity on [ATP] and on loads (both positive and negative). Furthermore, using the model we study the kinetics of a number of mutant kinesin homodimers and heterodimers, showing that the two heads' ATPase activities of some of these molecules are not well coordinated and they move processively with low mechanochemical coupling efficiencies even under no load. The theoretical results of ATPase rate per head, moving velocity, and stall force of the motors show good quantitative agreement with the experimental ones. The puzzling dynamic behaviours of mutant homodimeric and heterodimeric kinesins become understandable.
Collapse
Affiliation(s)
- Ping Xie
- Laboratory of Soft Matter Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China.
| | | | | |
Collapse
|
29
|
Nara I, Ishiwata S. Processivity of kinesin motility is enhanced on increasing temperature. Biophysics (Nagoya-shi) 2006; 2:13-21. [PMID: 27857556 PMCID: PMC5036643 DOI: 10.2142/biophysics.2.13] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2005] [Accepted: 01/11/2006] [Indexed: 12/01/2022] Open
Abstract
Kinesin is a motor protein that processively moves step by step along a microtubule. To investigate the effects of temperature on run length, i.e., processivity of kinesin motility, we performed a single-molecular bead assay at temperature range of 20–40°C. An increase in the walking velocity of kinesin corresponded to the Arrhenius activation enthalpy of 48 kJ/mol, being consistent with the previous reports. Here, we found that the run length increased, that is, the kinesin processivity enhanced with increasing temperature. Then, we estimated the probability of detachment of kinesin from a microtubule per one 8-nm stepping event, and found that it diminishes from 0.014 to 0.006/step with increasing temperature from 20 to 40°C. And we noticed that prolonged incubation at 30, 35 and 40°C significantly slowed down the walking velocity, but further increased the run length and duration. Those results are interpreted according to the effect of temperature on the rate constants of some key kinetic steps in the ATPase cycle.
Collapse
Affiliation(s)
- Ikuko Nara
- Department of Physics, School of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo169-8555, Japan
| | - Shin'ichi Ishiwata
- Department of Physics, School of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo169-8555, Japan; Advanced Research Institute for Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo169-8555, Japan
| |
Collapse
|
30
|
Xie P, Dou SX, Wang PY. Model for kinetics of myosin-V molecular motors. Biophys Chem 2005; 120:225-36. [PMID: 16386350 DOI: 10.1016/j.bpc.2005.11.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2005] [Revised: 11/22/2005] [Accepted: 11/22/2005] [Indexed: 10/25/2022]
Abstract
A hand-over-hand model is presented for the processive movement of myosin-V based on previous biochemical experimental results and structural observations of nucleotide-dependent conformational changes of single-headed myosins. The model shows that the ADP-release rate of the trailing head is much higher than that of the leading head, thus giving a 1:1 mechanochemical coupling for the processive movement of the motor. It explains well the previous finding that some 36-nm steps consist of two substeps, while other 36-nm steps consist of no substeps. Using the model, the calculated kinetic behaviors of myosin-V such as the main and intermediate dwell time distributions, the load dependence of the average main and intermediate dwell time and the load dependence of occurrence frequency of the intermediate state under various nucleotide conditions show good quantitative agreement with previous experimental results.
Collapse
Affiliation(s)
- Ping Xie
- Laboratory of Soft Matter Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China.
| | | | | |
Collapse
|
31
|
Carter NJ, Cross RA. Kinesin's moonwalk. Curr Opin Cell Biol 2005; 18:61-7. [PMID: 16361092 DOI: 10.1016/j.ceb.2005.12.009] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2005] [Accepted: 12/02/2005] [Indexed: 11/20/2022]
Abstract
Kinesin-1 is a single-molecule walking machine, driven by ATP turnover. Recent optical trapping experiments show that pulling backwards on a walking kinesin-1 molecule causes the mechanical walking action to reverse, while the coupled chemical cycle of ATP turnover continues, apparently, to run forwards -- kinesin can moonwalk. Individual forward- and back-steps are fast, and each appears to be a single event, complete in a few tens of microseconds, with no substeps. Between steps, kinesin pauses, waiting for the next ATP to arrive. Several lines of evidence indicate that during these between-step dwells, only one of the two heads is strongly attached to the microtubule. The position of the other head during the dwells is less certain, and more controversial.
Collapse
Affiliation(s)
- Nicholas J Carter
- Molecular Motors Group, Marie Curie Research Institute, The Chart, Oxted, Surrey, RH8 0TE UK
| | | |
Collapse
|
32
|
Laser literature watch. Photomed Laser Surg 2005; 23:513-24. [PMID: 16262584 DOI: 10.1089/pho.2005.23.513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
33
|
Yajima J, Cross RA. A torque component in the kinesin-1 power stroke. Nat Chem Biol 2005; 1:338-41. [PMID: 16408073 DOI: 10.1038/nchembio740] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2005] [Accepted: 09/20/2005] [Indexed: 11/09/2022]
Abstract
Kinesin-1 is a twin-headed molecular motor that moves along microtubules in 8-nm steps, using a walking action in which the two heads interact alternately with the microtubule. Constructs with only one head can also produce impulses of force and motion, indicating that the walking action is an amplification strategy that leverages an underlying force-generating event. Recent work suggests that directional force is produced either by directionally biased selection of microtubule binding sites or by a conformational change subsequent to the binding event. We report here that surface-attached rat kinesin-1 monomers drive counterclockwise rotation of sliding microtubules around their axes, and that by manipulating the assay geometry, we could reduce or block the torsional motion with negligible effects on the axial motion. We can account for this behavior on the simple assumption that kinesin heads tend to bind to the closest available tubulin heterodimer in the lattice, but only in the case where an additional biasing process is present that shifts the start position for diffusion-to-capture toward the microtubule plus end by approximately 1 nm.
Collapse
Affiliation(s)
- Junichiro Yajima
- Molecular Motors Group, Marie Curie Research Institute, The Chart, Oxted, Surrey RH8 0TL, UK
| | | |
Collapse
|
34
|
Chu HMA, Yun M, Anderson DE, Sage H, Park HW, Endow SA. Kar3 interaction with Cik1 alters motor structure and function. EMBO J 2005; 24:3214-23. [PMID: 16107877 PMCID: PMC1224680 DOI: 10.1038/sj.emboj.7600790] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2005] [Accepted: 07/28/2005] [Indexed: 11/09/2022] Open
Abstract
Kar3, a kinesin-14 motor of Saccharomyces cerevisiae required for mitosis and karyogamy, reportedly interacts with Cik1, a nonmotor protein, via its central, predicted coiled coil. Despite this, neither Kar3 nor Cik1 homodimers have been observed in vivo. Here we show that Kar3 is a dimer in vitro by analytical ultracentrifugation. The motor domains appear as paired particles by rotary-shadow electron microscopy (EM) and circular dichroism (CD) spectroscopy of the nonmotor region shows characteristics of helical structure, typical of coiled coils. Remarkably, the Kar3/Cik1 nonmotor region shows greater helicity by CD analysis and rotary-shadow EM reveals a stalk joined to one large or two smaller particles. The highly helical Kar3/Cik1 nonmotor region and visible stalk indicate that dimerization with Cik1 causes structural changes in Kar3. The Cik1 and Kar3 stalk regions preferentially associate with one another rather than forming homodimers. Kar3/Cik1 moves on microtubules at 2-2.4 microm min(-1), 2-5-fold faster than Kar3, and destabilizes microtubules at the lagging ends. Thus, structural changes in Kar3 upon dimerization with Cik1 alter the motor velocity and likely regulate Kar3 activity in vivo.
Collapse
Affiliation(s)
| | - Mikyung Yun
- Department of Structural Biology, St Jude Children's Research Hospital, Memphis, TN, USA
| | - David E Anderson
- Department of Cell Biology, Duke University Medical Center, Durham, NC, USA
| | - Harvey Sage
- Department of Biochemistry, Duke University Medical Center, Durham, NC, USA
| | - Hee-Won Park
- Department of Structural Biology, St Jude Children's Research Hospital, Memphis, TN, USA
| | - Sharyn A Endow
- Department of Cell Biology, Duke University Medical Center, Durham, NC, USA
- Department of Cell Biology, Duke University Medical Center, 450 Sands Building, Research Drive, Durham, NC 27710, USA. Tel.: +1 919 684 4311; Fax: +1 919 684 8090; E-mail:
| |
Collapse
|
35
|
Yildiz A, Selvin PR. Fluorescence imaging with one nanometer accuracy: application to molecular motors. Acc Chem Res 2005; 38:574-82. [PMID: 16028892 DOI: 10.1021/ar040136s] [Citation(s) in RCA: 222] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We introduce the technique of FIONA, fluorescence imaging with one nanometer accuracy. This is a fluorescence technique that is able to localize the position of a single dye within approximately 1 nm in the x-y plane. It is done simply by taking the point spread function of a single fluorophore excited with wide field illumination and locating the center of the fluorescent spot by a two-dimensional Gaussian fit. We motivate the development of FIONA by unraveling the walking mechanism of the molecular motors myosin V, myosin VI, and kinesin. We find that they all walk in a hand-over-hand fashion.
Collapse
Affiliation(s)
- Ahmet Yildiz
- Center for Biophysics and Computational Biology and Department of Physics, University of Illinois, Urbana-Champaign, Illinois 61801, USA
| | | |
Collapse
|
36
|
Kamei T, Kakuta S, Higuchi H. Biased binding of single molecules and continuous movement of multiple molecules of truncated single-headed kinesin. Biophys J 2004; 88:2068-77. [PMID: 15626711 PMCID: PMC1305259 DOI: 10.1529/biophysj.104.049759] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Conventional kinesin has a double-headed structure consisting of two motor domains and moves processively along a microtubule using the two heads cooperatively. The movement of single and multiple truncated heads of Drosophila kinesin was measured using a laser trap and nanometer detecting apparatus. Single molecules of single-headed kinesin bound to the microtubules with a 3.5 nm biased displacement toward the plus end of the microtubule. The position of these single-headed kinesin molecules bound to a microtubule did not change until they had dissociated, indicating that single kinesin heads utilize nonprocessive movement processes. Two molecules of single-headed kinesin moved continuously along a microtubule with a lower velocity and force than that of single molecules of double-headed kinesin. The biased binding of the heads determines the directionality of movement, whereas two molecules of single-headed kinesin move continuously without dissociation from a microtubule.
Collapse
Affiliation(s)
- Takashi Kamei
- Department of Metallurgy, School of Engineering, Tohoku University, Sendai 980-8579, Japan
| | | | | |
Collapse
|