Li, S. et al. Crystal structure of the cytoskeleton-associated protein (CAP-Gly) domain. J. Biol. Chem. 277, 48596-48601

University of Alabama at Birmingham, Birmingham, Alabama, United States
Journal of Biological Chemistry (Impact Factor: 4.57). 01/2003; 277(50):48596-601. DOI: 10.1074/jbc.M208512200
Source: PubMed


Cytoskeleton-associated proteins (CAPs) are involved in the organization of microtubules and transportation of vesicles and organelles along the cytoskeletal network. A conserved motif, CAP-Gly, has been identified in a number of CAPs, including CLIP-170 and dynactins. The crystal structure of the CAP-Gly domain of Caenorhabditis elegans F53F4.3 protein, solved by single wavelength sulfur-anomalous phasing, revealed a novel protein fold containing three beta-sheets. The most conserved sequence, GKNDG, is located in two consecutive sharp turns on the surface, forming the entrance to a groove. Residues in the groove are highly conserved as measured from the information content of the aligned sequences. The C-terminal tail of another molecule in the crystal is bound in this groove.

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Available from: Chi-Hao Luan, May 22, 2015
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    • "The second EB-binding mechanism involves the cytoskeletonassociated protein glycine-rich (CAP-Gly) domain of +TIPs and the evolutionary conserved EEY/F motif present at the very C-terminus of EBs (reviewed in Akhmanova and Steinmetz, 2010). The EEY/F motif, including its terminal a-carboxylate group, is specifically recognized by a conserved cavity encompassing the characteristic GKNDG motif of the CAP-Gly domain (Li et al., 2002; Weisbrich et al., 2007; Honnappa et al., 2006; Mishima et al., 2007). Prominent examples of +TIPs utilizing CAP-Gly domains to target EBs at growing microtubule ends include the cytoplasmic linker protein of 170 kDa (CLIP-170) and the large dynactin subunit p150 glued (Askham et al., 2002; Bu and Su, 2003; Komarova et al., 2005, 2002). "
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    ABSTRACT: End binding proteins (EBs) track growing microtubule ends and play a master role in organizing dynamic protein networks. Mammalian cells express up to three different EBs (EB1, EB2, and EB3). Besides forming homodimers, EB1 and EB3 also assemble into heterodimers. One group of EB-binding partners encompasses proteins that harbor CAP-Gly domains. The binding properties of the different EBs towards CAP-Gly proteins have not been systematically investigated. This information is, however, important to compare and contrast functional differences. Here we analyzed the interactions between CLIP-170 and p150(glued) CAP-Gly domains with the three EB homodimers and the EB1-EB3 heterodimer. Using isothermal titration calorimetry we observed that some EBs bind to the individual CAP-Gly domains with similar affinities while others interact with their targets with pronounced differences. We further found that the two types of CAP-Gly domains use alternative mechanisms to target the C-terminal domains of EBs. We succeeded to solve the crystal structure of a complex composed of a heterodimer of EB1 and EB3 C-termini together with the CAP-Gly domain of p150(glued). Together, our results provide mechanistic insights into the interaction properties of EBs and offer a molecular framework for the systematic investigation of their functional differences in cells.
    Full-text · Article · Nov 2011 · Journal of Structural Biology
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    • "The crystal structure of the CAP-Gly domain of TBCB in C. elegans, F53F4.3, shows a completely different fold with three antiparallel β-sheets [34]. However, despite this different topology with respect to the TBCC N-terminal domain, it also has a flexible α-helix at the N-terminus preceded by 17 disordered residues which were proposed to participate in intermolecular interactions [34]. "
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    ABSTRACT: Human Tubulin Binding Cofactor C (TBCC) is a post-chaperonin involved in the folding and assembly of α- and β-tubulin monomers leading to the release of productive tubulin heterodimers ready to polymerize into microtubules. In this process it collaborates with other cofactors (TBC's A, B, D, and E) and forms a supercomplex with TBCD, β-tubulin, TBCE and α-tubulin. Here, we demonstrate that TBCC depletion results in multipolar spindles and mitotic failure. Accordingly, TBCC is found at the centrosome and is implicated in bipolar spindle formation. We also determine by NMR the structure of the N-terminal domain of TBCC. The TBCC N-terminal domain adopts a spectrin-like fold topology composed of a left-handed 3-stranded α-helix bundle. Remarkably, the 30-residue N-terminal segment of the TBCC N-terminal domain is flexible and disordered in solution. This unstructured region is involved in the interaction with tubulin. Our data lead us to propose a testable model for TBCC N-terminal domain/tubulin recognition in which the highly charged N-terminus as well as residues from the three helices and the loops interact with the acidic hypervariable regions of tubulin monomers.
    Full-text · Article · Oct 2011 · PLoS ONE
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    • "The overall architecture is highly similar to the structure of the p150 Glued Cap-Gly domain and a Cap-Gly domain from a putative C. elegans α-tubulin folding chaperone, F53F4 (respective r.m.s.d. values of 0.9 Å and 1.1 Å over 213 mainchain atoms; Figure 5C)(Hayashi et al., 2005;Li et al., 2002). "
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    ABSTRACT: Microtubule plus end binding proteins (+TIPs) localize to the dynamic plus ends of microtubules, where they stimulate microtubule growth and recruit signaling molecules. Three main +TIP classes have been identified (XMAP215, EB1, and CLIP-170), but whether they act upon microtubule plus ends through a similar mechanism has not been resolved. Here, we report crystal structures of the tubulin binding domains of XMAP215 (yeast Stu2p and Drosophila Msps), EB1 (yeast Bim1p and human EB1), and CLIP-170 (human), which reveal diverse tubulin binding interfaces. Functional studies, however, reveal a common property that native or artificial dimerization of tubulin binding domains (including chemically induced heterodimers of EB1 and CLIP-170) induces tubulin nucleation/assembly in vitro and, in most cases, plus end tracking in living cells. We propose that +TIPs, although diverse in structure, share a common property of multimerizing tubulin, thus acting as polymerization chaperones that aid in subunit addition to the microtubule plus end.
    Preview · Article · Oct 2007 · Molecular Cell
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