This entry represents a conserved region within a number of eukaryotic dedicator of cytokinesis proteins (DOCK), which are guanine nucleotide exchange factors (GEFs)[1-3], that activate some small GTPases by exchanging bound GDP for free GTP such as Rac. These proteins have a DOCK-homology region 1 (DHR-1, also known as DOCK-type C2 domain) at the N-terminus and a DHR-2 (also known as DOCKER domain) at the C-terminal. The DHR-2 is a GEF catalytic domain organised into three lobes, A, B and C, with the Rho-family binding site and catalytic centre generated entirely from lobes B and C. This entry represents Lobe A, formed from an antiparallel array of alpha helices that adopts a tetratricopeptide repeat-like fold, which through extensive contacts with lobe B, stabilises DHR-2 domain [4,5].

1: Unconventional Rac-GEF activity is mediated through the Dock180-ELMO complex. Brugnera E, Haney L, Grimsley C, Lu M, Walk SF, Tosello-Trampont AC, Macara IG, Madhani H, Fink GR, Ravichandran KS; Nat Cell Biol. 2002;4:574-582. PMID:12134158

2: Identification of an evolutionarily conserved superfamily of DOCK180-related proteins with guanine nucleotide exchange activity. Cote JF, Vuori K; J Cell Sci. 2002;115:4901-4913. PMID:12432077

3: Structural basis for mutual relief of the Rac guanine nucleotide exchange factor DOCK2 and its partner ELMO1 from their autoinhibited forms. Hanawa-Suetsugu K, Kukimoto-Niino M, Mishima-Tsumagari C, Akasaka R, Ohsawa N, Sekine S, Ito T, Tochio N, Koshiba S, Kigawa T, Terada T, Shirouzu M, Nishikimi A, Uruno T, Katakai T, Kinashi T, Kohda D, Fukui Y, Yokoyama S; Proc Natl Acad Sci U S A. 2012;109:3305-3310. PMID:22331897

4: Structure of the DOCK2-ELMO1 complex provides insights into regulation of the auto-inhibited state. Chang L, Yang J, Jo CH, Boland A, Zhang Z, McLaughlin SH, Abu-Thuraia A, Killoran RC, Smith MJ, Cote JF, Barford D; Nat Commun. 2020;11:3464. PMID:32651375

5: Structural Basis for the Dual Substrate Specificity of DOCK7 Guanine Nucleotide Exchange Factor. Kukimoto-Niino M, Tsuda K, Ihara K, Mishima-Tsumagari C, Honda K, Ohsawa N, Shirouzu M; Structure. 2019;27:741-748. PMID:30853411