This domain is found in the type IV virulence effector SidM/DrrA from Legionella pneumophila. This protein has dual GEF and GDF activity specifically toward Rab1, a key regulator for endoplasmic reticulum (ER)-to-Golgi vesicle trafficking. SidM consists of an N-terminal helical domain (this entry), a Rab1-activation domain (Pfam:PF20851), and a C- terminal phosphatidylinositol 4-phosphate-binding (P4M) domain (Pfam:PF14860). The N-terminal is mostly alpha-helical, but also shows a short two-stranded beta-sheet [1,3].

1: Structural insights into the dual nucleotide exchange and GDI displacement activity of SidM/DrrA. Suh HY, Lee DW, Lee KH, Ku B, Choi SJ, Woo JS, Kim YG, Oh BH; EMBO J. 2010;29:496-504. PMID:19942850

2: RabGDI displacement by DrrA from Legionella is a consequence of its guanine nucleotide exchange activity. Schoebel S, Oesterlin LK, Blankenfeldt W, Goody RS, Itzen A; Mol Cell. 2009;36:1060-1072. PMID:20064470

3: Structural mechanism of host Rab1 activation by the bifunctional Legionella type IV effector SidM/DrrA. Zhu Y, Hu L, Zhou Y, Yao Q, Liu L, Shao F; Proc Natl Acad Sci U S A. 2010;107:4699-4704. PMID:20176951

4: High-affinity binding of phosphatidylinositol 4-phosphate by Legionella pneumophila DrrA. Schoebel S, Blankenfeldt W, Goody RS, Itzen A; EMBO Rep. 2010;11:598-604. PMID:20616805

5: Structural basis for PI(4)P-specific membrane recruitment of the Legionella pneumophila effector DrrA/SidM. Del Campo CM, Mishra AK, Wang YH, Roy CR, Janmey PA, Lambright DG; Structure. 2014;22:397-408. PMID:24530282