Adaptor protein, Phosphotyrosine interaction, PH domain and Leucine zipper containing (APPL) proteins are effectors of the small GTPase Rab5 that function in endosome-mediated signaling []. They contain BAR, pleckstrin homology (PH) and phosphotyrosine binding (PTB) domains. They form homo- and hetero-oligomers that are mediated by their BAR domains []. Vertebrates contain two APPL proteins, APPL1 and APPL2. APPL1 interacts with diverse receptors (e.g. NGF receptor TrkA, FSHR, adiponectin receptors) and signaling proteins (e.g. Akt, PI3K), and may function as an adaptor linked to many distinct signaling pathways []. This entry represents the BAR domain of APPL1.
OCRL1 hydrolyzes phosphatidylinositol 4,5-bisphosphate (PtIns(4,5)P2) and the signaling molecule phosphatidylinositol 1,4,5-trisphosphate (PtIns(1,4,5)P3), and thereby modulates cellular signaling events []. OCRL1 resides on vesicular structures throughout the endosomal system and the Golgi complex, and is also present at the plasma membrane in membrane ruffles and at late-stage endocytic clathrin-coated pits. It binds clathrin, clathrin adaptors, several GTPases, and the endocytic proteins APPL1 and Ses1/2 []. Mutations in the OCRL1 gene cause Lowe Syndrome, leading to cataracts, mental retardation and renal failure []. Mutations in OCRL can also give rise to a milder pathology, Dent disease 2, which is characterised by renal Fanconi syndrome in the absence of extrarenal pathologies [].OCRL1 shares ~45% sequence identity with INPP5B and has the same domain organization. However, a loop in the Rho GAP domain contains a second clathrin box which is absent in INPP5B. INPP5B shares most interacting partners with OCRL, except for clathrin and the endocytic clathrin adaptor AP-2 []. OCRL1 contains a PH domain, a 5-phosphatase domain, an ASH domain and a Rho-GAP domain. The RhoGAP domain lacks the catalytic arginine and is catalytically inactive. However, the RhoGAP domain of OCRL interacts with Rac and Cdc42, but only the Cdc42 interaction is GTP-dependent. The RhoGAP domain also interacts with three endocytic proteins containing the F&H motif: APPL1, Ses1 and Ses2. OCRL1 interacts with Rab GTPase (Rab8) through its ASH domain []. This entry represents the inositol polyphosphate 5-phosphatase (INPP5c) domain of OCRL1/INPP5B.
OCRL1 hydrolyzes phosphatidylinositol 4,5-bisphosphate (PtIns(4,5)P2) and the signaling molecule phosphatidylinositol 1,4,5-trisphosphate (PtIns(1,4,5)P3), and thereby modulates cellular signaling events []. OCRL1 resides on vesicular structures throughout the endosomal system and the Golgi complex, and is also present at the plasma membrane in membrane ruffles and at late-stage endocytic clathrin-coated pits. It binds clathrin, clathrin adaptors, several GTPases, and the endocytic proteins APPL1 and Ses1/2 []. Mutations in the OCRL1 gene cause Lowe Syndrome, leading to cataracts, mental retardation and renal failure []. Mutations in OCRL can also give rise to a milder pathology, Dent disease 2, which is characterised by renal Fanconi syndrome in the absence of extrarenal pathologies [].OCRL1 shares ~45% sequence identity with INPP5B (not included in this entry) and has the same domain organization. However, a loop in the Rho GAP domain contains a second clathrin box which is absent in INPP5B. INPP5B shares most interacting partners with OCRL, except for clathrin and the endocytic clathrin adaptor AP-2 []. OCRL1 contains a PH domain, a 5-phosphatase domain, an ASH domain and a Rho-GAP domain. The RhoGAP domain lacks the catalytic arginine and is catalytically inactive. However, the RhoGAP domain of OCRL interacts with Rac and Cdc42, but only the Cdc42 interaction is GTP-dependent. The RhoGAP domain also interacts with three endocytic proteins containing the F&H motif: APPL1, Ses1 and Ses2. OCRL1 interacts with Rab GTPase (Rab8) through its ASH domain []. This entry represents the PH domain of OCRL1 []. The PH domain connects to the 5-phosphatase domain, which has a Dnase I-like fold [].
