title: Structural basis for the extended CAP-Gly domains of p150(glued) binding to microtubules and the implication for tubulin dynamics.
abstract: p150(glued) belongs to a group of proteins accumulating at microtubule plus ends (+TIPs). It plays a key role in initiating retrograde transport by recruiting and tethering endosomes and dynein to microtubules. p150(glued) contains an N-terminal microtubule-binding cytoskeleton-associated protein glycine-rich (CAP-Gly) domain that accelerates tubulin polymerization. Although this copolymerization is well-studied using light microscopic techniques, structural consequences of this interaction are elusive. Here, using electron-microscopic and spectroscopic approaches, we provide a detailed structural view of p150(glued) CAP-Gly binding to microtubules and tubulin. Cryo-EM 3D reconstructions of p150(glued)-CAP-Gly complexed with microtubules revealed the recognition of the microtubule surface, including tubulin C-terminal tails by CAP-Gly. These binding surfaces differ from other retrograde initiation proteins like EB1 or dynein, which could facilitate the simultaneous attachment of all accessory components. Furthermore, the CAP-Gly domain, with its basic extensions, facilitates lateral and longitudinal interactions of tubulin molecules by covering the tubulin acidic tails. This shielding effect of CAP-Gly and its basic extensions may provide a molecular basis of the roles of p150(glued) in microtubule dynamics.
authors: Cellular and Membrane Trafficking, Max Planck Institute of Biochemistry, D-82152 Martinsried, Germany; and.
authors: Qianmin
authors: Q
authors: Wang
authors: Physical Chemistry, Department for Chemistry and Biochemistry and Center for NanoScience, Ludwig-Maximilians-Universität München, D-81377 Munich, Germany.
authors: Alvaro H
authors: AH
authors: Crevenna
authors: Cellular and Membrane Trafficking, Max Planck Institute of Biochemistry, D-82152 Martinsried, Germany; and.
authors: Ines
authors: I
authors: Kunze
authors: Cellular and Membrane Trafficking, Max Planck Institute of Biochemistry, D-82152 Martinsried, Germany; and mizuno@biochem.mpg.de.
authors: Naoko
authors: N
authors: Mizuno
mesh_terms: D003080:Cold Temperature; D020285:Cryoelectron Microscopy; D000072159:Dynactin Complex; D004398:Dyneins / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism; D006868:Hydrolysis; D007091:Image Processing, Computer-Assisted; D007700:Kinetics; D008869:Microtubule-Associated Proteins / Q000737:chemistry* / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism* / Q000648:ultrastructure; D010455:Peptides / Q000737:chemistry / Q000378:metabolism; D058105:Polymerization; D011485:Protein Binding; D055503:Protein Multimerization; D017434:Protein Structure, Tertiary; D017384:Sequence Deletion; D013329:Structure-Activity Relationship; D014404:Tubulin / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D000072159:Dynactin Complex; D008869:Microtubule-Associated Proteins; D010455:Peptides; D014404:Tubulin; D006160:Guanosine Triphosphate; D004398:Dyneins
keywords: cytoskeleton; dynactin; dynamic instability; electron microscopy