Phosphatidylinositol 3,4,5-trisphosphate-dependent Rac exchanger 1 protein (PREX1)

Phosphatidylinositol 3,4,5-trisphosphate-dependent Rac exchanger 1 protein (PREX1) is a guanine nucleotide exchange factor (GEF) that activates members of the Rac subfamily of Rho GTPases, primarily Rac1, by facilitating the exchange of GDP for GTP[3][2]. It is activated by phosphatidylinositol 3,4,5-trisphosphate (PIP3), a product of PI3K signaling, and by the beta-gamma subunits of heterotrimeric G proteins downstream of GPCR and receptor tyrosine kinase (RTK) activation[3][2]. PREX1 plays essential cellular roles including regulating cell migration, cytoskeletal organization, adhesion, and proliferation[2][3][6]. It is involved in the pathophysiology of cancer, particularly in breast cancer and melanoma, where its activity supports tumor growth, invasion, and metastasis[3][2][6]. Structurally, PREX1 contains several domains (DH, PH, DEP1, DEP2, IP4P, etc.) that collectively regulate its autoinhibition and activation; release of autoinhibition enables GEF activity toward Rac1[1][4][5]. PREX1 functions as part of negative feedback involving phosphorylation by kinases such as PAK1, which downregulate its activity when signaling needs to be terminated[2][1]. Due to its role in cancer and cell signaling, PREX1 is under investigation as a therapeutic target, with ongoing research into inhibitors and diagnostic relevance[2][3][6].

Other names

P-Rex1KIAA1415PtdIns(3,4,5)-dependent Rac exchanger 1PIP3-dependent Rac exchange factor 1phosphatidylinositol 3,4,5-trisphosphate dependent Rac exchange factor 1PREX1PREX-1

Inhibition (e.g., by reducing PREX1 expression or blocking upstream PI3K/Akt pathway); Modulation of phosphorylation (e.g., PAK inhibitors indirectly reducing PREX1 activity through phosphorylation[2])