InterPro domain: IPR045110

XMAP215 proteins, such as Alp14 and XMAP215 (also known as CKAP5), increase microtubules dynamic polymerization rates by recruiting soluble alpha/beta-tubulin via their conserved TOG domains to polymerizing microtubule plus ends [ 1 , 2 , 3 ]. The TOG domain contains HEAT repeats, forming a oblong paddle-like structure. CKAP5 plays a major role in organizing spindle poles and acts as component of the TACC3/ch-TOG/clathrin complex proposed to contribute to stabilization of kinetochore fibres of the mitotic spindle by acting as inter-microtubule bridge [ 4 ].

Proteins in this family also includes the XMAP215 homologue, Stu2 from budding yeasts [ 5 ] and Alp14/Dis1 from fission yeasts [ 6 ].

1. Regulation of microtubule dynamics by TOG-domain proteins XMAP215/Dis1 and CLASP. Trends Cell Biol. 21, 604-14
2. XMAP215 polymerase activity is built by combining multiple tubulin-binding TOG domains and a basic lattice-binding region. Proc Natl Acad Sci U S A 108, 2741-6
3. Reconstituting dynamic microtubule polymerization regulation by TOG domain proteins. Meth. Enzymol. 540, 131-48
4. XMAP215 activity sets spindle length by controlling the total mass of spindle microtubules. Nat Cell Biol 15, 1116-22
5. Stu2, the budding yeast XMAP215/Dis1 homolog, promotes assembly of yeast microtubules by increasing growth rate and decreasing catastrophe frequency. J Biol Chem 289, 28087-93
6. p93dis1, which is required for sister chromatid separation, is a novel microtubule and spindle pole body-associating protein phosphorylated at the Cdc2 target sites. Genes Dev 9, 1572-85