Structural highlights
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. [CDC42_HUMAN] Plasma membrane-associated small GTPase which cycles between an active GTP-bound and an inactive GDP-bound state. In active state binds to a variety of effector proteins to regulate cellular responses. Involved in epithelial cell polarization processes. Regulates the bipolar attachment of spindle microtubules to kinetochores before chromosome congression in metaphase. Plays a role in the extension and maintenance of the formation of thin, actin-rich surface projections called filopodia. Mediates CDC42-dependent cell migration.[1] [2] [3]
Publication Abstract from PubMed
Phosphatidylinositol 3,4,5-trisphosphate (PIP3)-dependent Rac exchanger 1 (P-Rex1) is a Rho guanine nucleotide exchange factor synergistically activated by PIP3 and Gbetagamma that plays an important role in the metastasis of breast, prostate, and skin cancer, making it an attractive therapeutic target. However, the molecular mechanisms behind P-Rex1 regulation are poorly understood. We determined structures of the P-Rex1 pleckstrin homology (PH) domain bound to the headgroup of PIP3 and resolved that PIP3 binding to the PH domain is required for P-Rex1 activity in cells but not for membrane localization, which points to an allosteric activation mechanism by PIP3. We also determined structures of the P-Rex1 tandem Dbl homology/PH domains in complexes with two of its substrate GTPases, Rac1 and Cdc42. Collectively, this study provides important molecular insights into P-Rex1 regulation and tools for targeting the PIP3-binding pocket of P-Rex1 with a new generation of cancer chemotherapeutic agents.
Structural and Biochemical Characterization of the Catalytic Core of the Metastatic Factor P-Rex1 and Its Regulation by PtdIns(3,4,5)P3.,Cash JN, Davis EM, Tesmer JJ Structure. 2016 May 3;24(5):730-40. doi: 10.1016/j.str.2016.02.022. Epub 2016 Apr, 14. PMID:27150042[4]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Gauthier-Campbell C, Bredt DS, Murphy TH, El-Husseini Ael-D. Regulation of dendritic branching and filopodia formation in hippocampal neurons by specific acylated protein motifs. Mol Biol Cell. 2004 May;15(5):2205-17. Epub 2004 Feb 20. PMID:14978216 doi:10.1091/mbc.E03-07-0493
- ↑ Oceguera-Yanez F, Kimura K, Yasuda S, Higashida C, Kitamura T, Hiraoka Y, Haraguchi T, Narumiya S. Ect2 and MgcRacGAP regulate the activation and function of Cdc42 in mitosis. J Cell Biol. 2005 Jan 17;168(2):221-32. Epub 2005 Jan 10. PMID:15642749 doi:10.1083/jcb.200408085
- ↑ Modzelewska K, Newman LP, Desai R, Keely PJ. Ack1 mediates Cdc42-dependent cell migration and signaling to p130Cas. J Biol Chem. 2006 Dec 8;281(49):37527-35. Epub 2006 Oct 12. PMID:17038317 doi:10.1074/jbc.M604342200
- ↑ Cash JN, Davis EM, Tesmer JJ. Structural and Biochemical Characterization of the Catalytic Core of the Metastatic Factor P-Rex1 and Its Regulation by PtdIns(3,4,5)P3. Structure. 2016 May 3;24(5):730-40. doi: 10.1016/j.str.2016.02.022. Epub 2016 Apr, 14. PMID:27150042 doi:http://dx.doi.org/10.1016/j.str.2016.02.022
