ECT2 (Epithelial Cell Transforming Sequence 2) is a guanine nucleotide exchange factor (GEF) that catalyses the exchange of GDP for GTP. It is a cell cycle regulator that plays key roles in cytokinesis [1]. ECT2 contains triple copies of the BRCT domain (BRCT0, BRCT1 (Pfam:PF12738) and BRCT2 (Pfam:PF00533) at the N-terminal, separated from the C-terminal DH (Pfam:PF00621) and PH domains by a linker of about 100 residues. This entry represents the PH domain [1]. The BRCT and DH-PH domains mediate intra-molecular interactions that restrains ETC2 activity during interphase.

1: Crystal structure of triple-BRCT-domain of ECT2 and insights into the binding characteristics to CYK-4. Zou Y, Shao Z, Peng J, Li F, Gong D, Wang C, Zuo X, Zhang Z, Wu J, Shi Y, Gong Q; FEBS Lett. 2014;588:2911-2920. PMID:25068414