2x0c

Publication Abstract from PubMed

Talin is an adaptor protein that couples integrins to F-actin. Structural studies show that the N-terminal talin head contains an atypical FERM domain while the N- and C-terminal parts of the talin rod comprise a series of alpha-helical bundles. However, determining the structure of the central part of the rod has proved problematic. Residues 1359-1659 are homologous to the MESDc1 gene product, and we therefore expressed this region of talin in E. coli. The crystal structure shows a unique fold comprised of a 5- and 4-helix bundle. The 5-helix bundle is composed of non-sequential helices due to insertion of the 4-helix bundle into the loop at the C-terminus of helix alpha3. The linker connecting the bundles forms a two-stranded anti-parallel beta-sheet likely limiting the relative movement of the two bundles. Because the 5-helix bundle contains the N- and C-termini of this module, we propose that it is linked by short loops to adjacent bundles while the 4-helix bundle protrudes from the rod. This suggests the 4-helix bundle has a unique role, and its pI (7.8) is higher than other rod domains. Both helical bundles contain vinculin-binding sites, but that in the isolated 5-helix bundle is cryptic whereas that in the isolated 4-helix bundle is constitutively active. In contrast, both bundles are required for actin binding. Finally, we show that the MESDc1 protein, which is predicted to have a similar fold, is a novel actin binding protein.

The central region of talin has a unique fold that binds vinculin and actin.,Gingras AR, Bate N, Goult BT, Patel B, Kopp PM, Emsley J, Barsukov IL, Roberts GC, Critchley DR J Biol Chem. 2010 Jul 7. PMID:20610383^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.