title: Internal dynamics of dynactin CAP-Gly is regulated by microtubules and plus end tracking protein EB1.
abstract: CAP-Gly domain of dynactin, a microtubule-associated activator of dynein motor, participates in multiple cellular processes, and its point mutations are associated with neurodegenerative diseases. Recently, we have demonstrated that conformational plasticity is an intrinsic property of CAP-Gly. To understand its origin, we addressed internal dynamics of CAP-Gly assembled on polymeric microtubules, bound to end-binding protein EB1 and free, by magic angle spinning NMR and molecular dynamics simulations. The analysis of residue-specific dynamics of CAP-Gly on time scales spanning nano- through milliseconds reveals its unusually high mobility, both free and assembled on polymeric microtubules. On the contrary, CAP-Gly bound to EB1 is significantly more rigid. Molecular dynamics simulations indicate that these motions are strongly temperature-dependent, and loop regions are surprisingly mobile. These findings establish the connection between conformational plasticity and internal dynamics in CAP-Gly, which is essential for the biological functions of CAP-Gly and its ability to bind to polymeric microtubules and multiple binding partners. In this work, we establish an approach, for the first time, to probe atomic resolution dynamic profiles of a microtubule-associated protein assembled on polymeric microtubules. More broadly, the methodology established here can be applied for atomic resolution analysis of dynamics in other microtubule-associated protein assemblies, including but not limited to dynactin, dynein, and kinesin motors assembled on microtubules.
authors.affiliation: From the Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716 and.
authors.forename: Si
authors.initials: S
authors.lastname: Yan
authors.affiliation: From the Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716 and.
authors.forename: Huilan
authors.initials: H
authors.lastname: Zhang
authors.affiliation: From the Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716 and.
authors.forename: Guangjin
authors.initials: G
authors.lastname: Hou
authors.affiliation: the Department of Molecular Medicine, Beckman Research Institute of City of Hope, Duarte, California 91010.
authors.forename: Shubbir
authors.initials: S
authors.lastname: Ahmed
authors.affiliation: the Department of Molecular Medicine, Beckman Research Institute of City of Hope, Duarte, California 91010.
authors.forename: John C
authors.initials: JC
authors.lastname: Williams
authors.affiliation: From the Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716 and tpolenov@udel.edu.
authors.forename: Tatyana
authors.initials: T
authors.lastname: Polenova
mesh_terms: D000818:Animals; D001665:Binding Sites; D003198:Computer Simulation; D003599:Cytoskeleton / Q000378:metabolism; D000072159:Dynactin Complex; D004398:Dyneins / Q000378:metabolism; D016547:Kinesins / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism*; D056004:Molecular Dynamics Simulation; D011336:Probability; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D051381:Rats; D013696:Temperature
chemical_list: D000072159:Dynactin Complex; C561584:Mapre1 protein, rat; D008869:Microtubule-Associated Proteins; D004398:Dyneins; D016547:Kinesins
keywords: Biophysics; CAP-Gy; Cytoskeleton; Dynactin; Magic Angle Spinning NMR; Microtubule; Microtubule-associated Protein; Molecular Dynamics; Protein Structure