6vsk

From Proteopedia

Crystal structure of the P-Rex1 DEP1 domain

Structural highlights

6vsk is a 1 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 3.12Å
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

PREX1_HUMAN Functions as a RAC guanine nucleotide exchange factor (GEF), which activates the Rac proteins by exchanging bound GDP for free GTP. Its activity is synergistically activated by phosphatidylinositol 3,4,5-trisphosphate and the beta gamma subunits of heterotrimeric G protein. May function downstream of heterotrimeric G proteins in neutrophils.

Publication Abstract from PubMed

Phosphatidylinositol (3,4,5)-trisphosphate (PIP(3))-dependent Rac exchanger 1 (P-Rex1) catalyzes the exchange of GDP for GTP on Rac GTPases, thereby triggering changes in the actin cytoskeleton and in transcription. Its overexpression is highly correlated with the metastasis of certain cancers. P-Rex1 recruitment to the plasma membrane and its activity are regulated via interactions with heterotrimeric Gbetagamma subunits, PIP(3), and protein kinase A (PKA). Deletion analysis has further shown that domains C-terminal to its catalytic Dbl homology (DH) domain confer autoinhibition. Among these, the first dishevelled, Egl-10, and pleckstrin domain (DEP1) remains to be structurally characterized. DEP1 also harbors the primary PKA phosphorylation site, suggesting that an improved understanding of this region could substantially increase our knowledge of P-Rex1 signaling and open the door to new selective chemotherapeutics. Here we show that the DEP1 domain alone can autoinhibit activity in context of the DH/PH-DEP1 fragment of P-Rex1 and interacts with the DH/PH domains in solution. The 3.1 A crystal structure of DEP1 features a domain swap, similar to that observed previously in the Dvl2 DEP domain, involving an exposed basic loop that contains the PKA site. Using purified proteins, we show that although DEP1 phosphorylation has no effect on the activity or solution conformation of the DH/PH-DEP1 fragment, it inhibits binding of the DEP1 domain to liposomes containing phosphatidic acid. Thus, we propose that PKA phosphorylation of the DEP1 domain hampers P-Rex1 binding to negatively charged membranes in cells, freeing the DEP1 domain to associate with and inhibit the DH/PH module.

The first DEP domain of the RhoGEF P-Rex1 autoinhibits activity and contributes to membrane binding.,Ravala SK, Hopkins JB, Plescia CB, Allgood SR, Kane MA, Cash JN, Stahelin RV, Tesmer JJG J Biol Chem. 2020 Sep 4;295(36):12635-12647. doi: 10.1074/jbc.RA120.014534. Epub , 2020 Jul 13. PMID:32661198^[1]

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

References

↑ Ravala SK, Hopkins JB, Plescia CB, Allgood SR, Kane MA, Cash JN, Stahelin RV, Tesmer JJG. The first DEP domain of the RhoGEF P-Rex1 autoinhibits activity and contributes to membrane binding. J Biol Chem. 2020 Sep 4;295(36):12635-12647. PMID:32661198 doi:10.1074/jbc.RA120.014534