1
|
Janakaloti Narayanareddy BR, Allipeta NR, Allard J, Gross SP. A new method to experimentally quantify dynamics of initial protein-protein interactions. Commun Biol 2024; 7:311. [PMID: 38472292 PMCID: PMC10933273 DOI: 10.1038/s42003-024-05914-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Accepted: 02/12/2024] [Indexed: 03/14/2024] Open
Abstract
Cells run on initiation of protein-protein interactions, which are dynamically tuned spatially and temporally to modulate cellular events. This tuning can be physical, such as attaching the protein to a cargo or protein complex, thereby altering its diffusive properties, or modulating the distance between protein pairs, or chemical, by altering the proteins' conformations (e.g., nucleotide binding state of an enzyme, post-translational modification of a protein, etc.). Because a dynamic and changing subset of proteins in the cell could be in any specific state, ensemble measurements are not ideal-to untangle which of the factors are important, and how, we need single-molecule measurements. Experimentally, until now we have not had good tools to precisely measure initiation of such protein-protein interactions at the single-molecule level. Here, we develop a new method to measure dynamics of initial protein-protein interactions, allowing measurement of how properties such as the distance between proteins, and their tethered length can modulate the rate of interactions. In addition to precise measurement distance dependent motor-MT rebinding dynamics, we demonstrate the use of a dithered optical trap to measure dynamic motor-MT interactions and further discuss the possibilities of this technique being applicable to other systems.
Collapse
Affiliation(s)
| | - Nathan Reddy Allipeta
- Developmental and Cell Biology, University of California Irvine, Irvine, CA, USA
- Arcadia High School, Arcadia, CA, USA
| | - Jun Allard
- Department of Mathematics, University of California Irvine, Irvine, CA, USA
| | - Steven P Gross
- Developmental and Cell Biology, University of California Irvine, Irvine, CA, USA.
| |
Collapse
|
2
|
Sen A, Chowdhury D, Kunwar A. Coordination, cooperation, competition, crowding and congestion of molecular motors: Theoretical models and computer simulations. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2024; 141:563-650. [PMID: 38960486 DOI: 10.1016/bs.apcsb.2023.12.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/05/2024]
Abstract
Cytoskeletal motor proteins are biological nanomachines that convert chemical energy into mechanical work to carry out various functions such as cell division, cell motility, cargo transport, muscle contraction, beating of cilia and flagella, and ciliogenesis. Most of these processes are driven by the collective operation of several motors in the crowded viscous intracellular environment. Imaging and manipulation of the motors with powerful experimental probes have been complemented by mathematical analysis and computer simulations of the corresponding theoretical models. In this article, we illustrate some of the key theoretical approaches used to understand how coordination, cooperation and competition of multiple motors in the crowded intra-cellular environment drive the processes that are essential for biological function of a cell. In spite of the focus on theory, experimentalists will also find this article as an useful summary of the progress made so far in understanding multiple motor systems.
Collapse
Affiliation(s)
- Aritra Sen
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra, India
| | - Debashish Chowdhury
- Department of Physics, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh, India
| | - Ambarish Kunwar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra, India.
| |
Collapse
|
3
|
Nguyen T, Narayanareddy BJ, Gross SP, Miles CE. ADP release can explain spatially-dependent kinesin binding times. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.08.563482. [PMID: 37986962 PMCID: PMC10659338 DOI: 10.1101/2023.11.08.563482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
The self-organization of cells relies on the profound complexity of protein-protein interactions. Challenges in directly observing these events have hindered progress toward understanding their diverse behaviors. One notable example is the interaction between molecular motors and cytoskeletal systems that combine to perform a variety of cellular functions. In this work, we leverage theory and experiments to identify and quantify the rate-limiting mechanism of the initial association between a cargo-bound kinesin motor and a microtubule track. Recent advances in optical tweezers provide binding times for several lengths of kinesin motors trapped at varying distances from a microtubule, empowering the investigation of competing models. We first explore a diffusion-limited model of binding. Through Brownian dynamics simulations and simulation-based inference, we find this simple diffusion model fails to explain the experimental binding times, but an extended model that accounts for the ADP state of the molecular motor agrees closely with the data, even under the scrutiny of penalizing for additional model complexity. We provide quantification of both kinetic rates and biophysical parameters underlying the proposed binding process. Our model suggests that most but not every motor binding event is limited by their ADP state. Lastly, we predict how these association rates can be modulated in distinct ways through variation of environmental concentrations and spatial distances.
Collapse
Affiliation(s)
- Trini Nguyen
- Center for Complex Biological Systems, University of California, Irvine, Irvine, CA 92697
| | | | - Steven P. Gross
- Center for Complex Biological Systems, University of California, Irvine, Irvine, CA 92697
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA 92697
- Department of Physics and Astronomy, University of California, Irvine, Irvine, CA 92697
- Department of Biomedical Engineering, University of California, Irvine, Irvine, CA 92697
| | - Christopher E. Miles
- Center for Complex Biological Systems, University of California, Irvine, Irvine, CA 92697
- Department of Mathematics, University of California, Irvine, Irvine, CA 92697
- Center for Multiscale Cell Fate, University of California, Irvine, Irvine, CA 92697
| |
Collapse
|
4
|
Tom AM, Kim WK, Hyeon C. Polymer brush-induced depletion interactions and clustering of membrane proteins. J Chem Phys 2021; 154:214901. [PMID: 34240971 DOI: 10.1063/5.0048554] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
We investigate the effect of mobile polymer brushes on proteins embedded in biological membranes by employing both Asakura-Oosawa type of theoretical model and coarse-grained molecular dynamics simulations. The brush polymer-induced depletion attraction between proteins changes non-monotonically with the size of brush. The depletion interaction, which is determined by the ratio of the protein size to the grafting distance between brush polymers, increases linearly with the brush size as long as the polymer brush height is shorter than the protein size. When the brush height exceeds the protein size, however, the depletion attraction among proteins is slightly reduced. We also explore the possibility of the brush polymer-induced assembly of a large protein cluster, which can be related to one of many molecular mechanisms underlying recent experimental observations of integrin nanocluster formation and signaling.
Collapse
Affiliation(s)
- Anvy Moly Tom
- Korea Institute for Advanced Study, Seoul 02455, South Korea
| | - Won Kyu Kim
- Korea Institute for Advanced Study, Seoul 02455, South Korea
| | - Changbong Hyeon
- Korea Institute for Advanced Study, Seoul 02455, South Korea
| |
Collapse
|
5
|
Gruebele M, Pielak GJ. Dynamical spectroscopy and microscopy of proteins in cells. Curr Opin Struct Biol 2021; 70:1-7. [PMID: 33662744 DOI: 10.1016/j.sbi.2021.02.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 02/01/2021] [Indexed: 12/31/2022]
Abstract
With a strong understanding of how proteins fold in hand, it is now possible to ask how in-cell environments modulate their folding, binding and function. Studies accessing fast (ns to s) in-cell dynamics have accelerated over the past few years through a combination of in-cell NMR spectroscopy and time-resolved fluorescence microscopies. Here, we discuss this recent work and the emerging picture of protein surfaces as not just hydrophilic coats interfacing the solvent to the protein's core and functional regions, but as critical components in cells controlling protein mobility, function and communication with post-translational modifications.
Collapse
Affiliation(s)
- Martin Gruebele
- Department of Chemistry, Department of Physics, and Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
| | - Gary J Pielak
- Departments of Chemistry, Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599, USA.
| |
Collapse
|
6
|
VanDelinder V, Sickafoose I, Imam ZI, Ko R, Bachand GD. The effects of osmolytes on in vitro kinesin-microtubule motility assays. RSC Adv 2020; 10:42810-42815. [PMID: 35514903 PMCID: PMC9057942 DOI: 10.1039/d0ra08148e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 11/18/2020] [Indexed: 01/05/2023] Open
Abstract
The gliding motility of microtubule filaments has been used to study the biophysical properties of kinesin motors, as well as being used in a variety of nanotechnological applications. While microtubules are generally stabilized in vitro with paclitaxel (Taxol®), osmolytes such as polyethylene glycol (PEG) and trimethylamine N-oxide (TMAO) are also able to inhibit depolymerization over extended periods of time. High concentrations of TMAO have also been reported to reversibly inhibit kinesin motility of paclitaxel-stabilized microtubules. Here, we examined the effects of the osmolytes PEG, TMAO, and glycerol on stabilizing microtubules during gliding motility on kinesin-coated substrates. As previously observed, microtubule depolymerization was inhibited in a concentration dependent manner by the addition of the different osmolytes. Kinesin-driven motility also exhibited concentration dependent effects with the addition of the osmolytes, specifically reducing the velocity, increasing rates of pinning, and altering trajectories of the microtubules. These data suggest that there is a delicate balance between the ability of osmolytes to stabilize microtubules without inhibiting motility. Overall, these findings provide a more comprehensive understanding of how osmolytes affect the dynamics of microtubules and kinesin motors, and their interactions in crowded environments.
Collapse
Affiliation(s)
- Virginia VanDelinder
- Center for Integrated Nanotechnologies, Sandia National Laboratories Albuquerque NM USA
| | - Ian Sickafoose
- Center for Integrated Nanotechnologies, Sandia National Laboratories Albuquerque NM USA
| | - Zachary I Imam
- Center for Integrated Nanotechnologies, Sandia National Laboratories Albuquerque NM USA
| | - Randy Ko
- Center for Integrated Nanotechnologies, Sandia National Laboratories Albuquerque NM USA
| | - George D Bachand
- Center for Integrated Nanotechnologies, Sandia National Laboratories Albuquerque NM USA
| |
Collapse
|
7
|
Xie P. Theoretical Analysis of Dynamics of Kinesin Molecular Motors. ACS OMEGA 2020; 5:5721-5730. [PMID: 32226850 PMCID: PMC7097908 DOI: 10.1021/acsomega.9b03738] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 01/23/2020] [Indexed: 05/07/2023]
Abstract
Kinesin is a typical molecular motor that can step processively on microtubules powered by hydrolysis of adenosine triphosphate (ATP) molecules, playing a critical role in intracellular transports. Its dynamical properties such as its velocity, stepping ratio, run length, dissociation rate, etc. as well as the load dependencies of these quantities have been well documented through single-molecule experimental methods. In particular, the run length shows a dramatic asymmetry with respect to the direction of the load, and the dissociation rate exhibits a slip-catch-slip bond behavior under the backward load. Here, an analytic theory was provided for the dynamics of kinesin motors under both forward and backward loads, explaining consistently and quantitatively the diverse available experimental results.
Collapse
|
8
|
A 6-nm ultra-photostable DNA FluoroCube for fluorescence imaging. Nat Methods 2020; 17:437-441. [PMID: 32203385 PMCID: PMC7138518 DOI: 10.1038/s41592-020-0782-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 02/12/2020] [Indexed: 12/17/2022]
Abstract
Photobleaching limits extended imaging of fluorescent biological samples. Here, we developed DNA based “FluoroCubes” that are similar in size to the green fluorescent protein (GFP), have single-point attachment to proteins, have a ~54-fold higher photobleaching lifetime and emit ~43-fold more photons than single organic dyes. We demonstrate that DNA FluoroCubes provide outstanding tools for single-molecule imaging, allowing the tracking of single motor proteins for >800 steps with nanometer precision.
Collapse
|
9
|
Guo SK, Shi XX, Wang PY, Xie P. Force dependence of unbinding rate of kinesin motor during its processive movement on microtubule. Biophys Chem 2019; 253:106216. [PMID: 31288174 DOI: 10.1016/j.bpc.2019.106216] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 06/26/2019] [Accepted: 06/30/2019] [Indexed: 12/15/2022]
Abstract
Kinesin is a biological molecular motor that can move continuously on microtubule until it unbinds. Here, we studied computationally the force dependence of the unbinding rate of the motor. Our results showed that while the unbinding rate under the forward load has the expected characteristic of "slip bond", with the unbinding rate increasing monotonically with the increase of the forward load, the unbinding rate under the backward load shows counterintuitive characteristic of "slip-catch-slip bond": as the backward load increases, the unbinding rate increases exponentially firstly, then drops rapidly and then increases again. Our calculated data are in agreement with the available single-molecule data from different research groups. The mechanism of the slip-catch-slip bond was revealed.
Collapse
Affiliation(s)
- Si-Kao Guo
- Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Science, Beijing 100190, China; School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiao-Xuan Shi
- Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Science, Beijing 100190, China; School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Peng-Ye Wang
- Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Science, Beijing 100190, China; School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ping Xie
- Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Science, Beijing 100190, China; School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
| |
Collapse
|
10
|
Arpağ G, Norris SR, Mousavi SI, Soppina V, Verhey KJ, Hancock WO, Tüzel E. Motor Dynamics Underlying Cargo Transport by Pairs of Kinesin-1 and Kinesin-3 Motors. Biophys J 2019; 116:1115-1126. [PMID: 30824116 PMCID: PMC6428962 DOI: 10.1016/j.bpj.2019.01.036] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 05/25/2018] [Accepted: 01/03/2019] [Indexed: 01/01/2023] Open
Abstract
Intracellular cargo transport by kinesin family motor proteins is crucial for many cellular processes, particularly vesicle transport in axons and dendrites. In a number of cases, the transport of specific cargo is carried out by two classes of kinesins that move at different speeds and thus compete during transport. Despite advances in single-molecule characterization and modeling approaches, many questions remain regarding the effect of intermotor tension on motor attachment/reattachment rates during cooperative multimotor transport. To understand the motor dynamics underlying multimotor transport, we analyzed the complexes of kinesin-1 and kinesin-3 motors attached through protein scaffolds moving on immobilized microtubules in vitro. To interpret the observed behavior, simulations were carried out using a model that incorporated motor stepping, attachment/detachment rates, and intermotor force generation. In single-molecule experiments, isolated kinesin-3 motors moved twofold faster and had threefold higher landing rates than kinesin-1. When the positively charged loop 12 of kinesin-3 was swapped with that of kinesin-1, the landing rates reversed, indicating that this "K-loop" is a key determinant of the motor reattachment rate. In contrast, swapping loop 12 had negligible effects on motor velocities. Two-motor complexes containing one kinesin-1 and one kinesin-3 moved at different speeds depending on the identity of their loop 12, indicating the importance of the motor reattachment rate on the cotransport speed. Simulations of these loop-swapped motors using experimentally derived motor parameters were able to reproduce the experimental results and identify best fit parameters for the motor reattachment rates for this geometry. Simulation results also supported previous work, suggesting that kinesin-3 microtubule detachment is very sensitive to load. Overall, the simulations demonstrate that the transport behavior of cargo carried by pairs of kinesin-1 and -3 motors are determined by three properties that differ between these two families: the unloaded velocity, the load dependence of detachment, and the motor reattachment rate.
Collapse
Affiliation(s)
- Göker Arpağ
- Department of Physics, Worcester Polytechnic Institute, Worcester, Massachusetts
| | - Stephen R Norris
- Department of Biophysics, University of Michigan, Ann Arbor, Michigan; Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan
| | - S Iman Mousavi
- Department of Physics, Worcester Polytechnic Institute, Worcester, Massachusetts
| | | | - Kristen J Verhey
- Department of Biophysics, University of Michigan, Ann Arbor, Michigan; Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan
| | - William O Hancock
- Department of Biomedical Engineering, Pennsylvania State University, State College, Pennsylvania.
| | - Erkan Tüzel
- Department of Physics, Worcester Polytechnic Institute, Worcester, Massachusetts.
| |
Collapse
|
11
|
Li Q, Tseng KF, King SJ, Qiu W, Xu J. A fluid membrane enhances the velocity of cargo transport by small teams of kinesin-1. J Chem Phys 2018; 148:123318. [PMID: 29604873 DOI: 10.1063/1.5006806] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Kinesin-1 (hereafter referred to as kinesin) is a major microtubule-based motor protein for plus-end-directed intracellular transport in live cells. While the single-molecule functions of kinesin are well characterized, the physiologically relevant transport of membranous cargos by small teams of kinesins remains poorly understood. A key experimental challenge remains in the quantitative control of the number of motors driving transport. Here we utilized "motile fraction" to overcome this challenge and experimentally accessed transport by a single kinesin through the physiologically relevant transport by a small team of kinesins. We used a fluid lipid bilayer to model the cellular membrane in vitro and employed optical trapping to quantify the transport of membrane-enclosed cargos versus traditional membrane-free cargos under identical conditions. We found that coupling motors via a fluid membrane significantly enhances the velocity of cargo transport by small teams of kinesins. Importantly, enclosing a cargo in a fluid lipid membrane did not impact single-kinesin transport, indicating that membrane-dependent velocity enhancement for team-based transport arises from altered interactions between kinesins. Our study demonstrates that membrane-based coupling between motors is a key determinant of kinesin-based transport. Enhanced velocity may be critical for fast delivery of cargos in live cells.
Collapse
Affiliation(s)
- Qiaochu Li
- Department of Physics, University of California, Merced, California 95343, USA
| | - Kuo-Fu Tseng
- Department of Physics, Oregon State University, Corvallis, Oregon 97331, USA
| | - Stephen J King
- Burnett School of Biomedical Sciences, University of Central Florida, Orlando, Florida 32827, USA
| | - Weihong Qiu
- Department of Physics, Oregon State University, Corvallis, Oregon 97331, USA
| | - Jing Xu
- Department of Physics, University of California, Merced, California 95343, USA
| |
Collapse
|
12
|
Dynamic coordination of two-metal-ions orchestrates λ-exonuclease catalysis. Nat Commun 2018; 9:4404. [PMID: 30353000 PMCID: PMC6199318 DOI: 10.1038/s41467-018-06750-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 09/22/2018] [Indexed: 11/08/2022] Open
Abstract
Metal ions at the active site of an enzyme act as cofactors, and their dynamic fluctuations can potentially influence enzyme activity. Here, we use λ-exonuclease as a model enzyme with two Mg2+ binding sites and probe activity at various concentrations of magnesium by single-molecule-FRET. We find that while MgA2+ and MgB2+ have similar binding constants, the dissociation rate of MgA2+ is two order of magnitude lower than that of MgB2+ due to a kinetic-barrier-difference. At physiological Mg2+ concentration, the MgB2+ ion near the 5'-terminal side of the scissile phosphate dissociates each-round of degradation, facilitating a series of DNA cleavages via fast product-release concomitant with enzyme-translocation. At a low magnesium concentration, occasional dissociation and slow re-coordination of MgA2+ result in pauses during processive degradation. Our study highlights the importance of metal-ion-coordination dynamics in correlation with the enzymatic reaction-steps, and offers insights into the origin of dynamic heterogeneity in enzymatic catalysis.
Collapse
|