The RhoGEF domain of AKAP-Lbc (AKAP13) catalyses nucleotide exchange on RhoA and is involved in development of cardiac hypertrophy. The RhoGEF activity of AKAP-Lbc has also been implicated in cancer. We have determined the X-ray crystal structure of the complex between RhoA:GDP and the AKAP-Lbc RhoGEF (DH-PH) domain to 2.1 A resolution. The structure reveals important differences compared to related RhoGEF proteins such as Leukemia-associated RhoGEF. Nucleotide exchange assays comparing the activity of the DH-PH domain to the DH domain alone showed no role for the PH domain in nucleotide exchange, which is explained by the RhoA:AKAP-Lbc structure. Comparison to a structure of the isolated AKAP-Lbc DH domain revealed a change in conformation of the N-terminal 'GEF switch' region upon binding to RhoA. Isothermal titration calorimetry showed that AKAP-Lbc has only micromolar affinity for RhoA which combined with the presence of potential binding pockets for small molecules on AKAP-Lbc raises the possibility of targeting AKAP-Lbc with guanine nucleotide exchange factor inhibitors.
The Crystal Structure of the RhoA : AKAP-Lbc DH-PH Domain Complex.,Abdul Azeez KR, Knapp S, Fernandes JM, Klussmann E, Elkins JM Biochem J. 2014 Sep 4. PMID:25186459[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
↑ Abdul Azeez KR, Knapp S, Fernandes JM, Klussmann E, Elkins JM. The Crystal Structure of the RhoA : AKAP-Lbc DH-PH Domain Complex. Biochem J. 2014 Sep 4. PMID:25186459 doi:http://dx.doi.org/10.1042/BJ20140606
