Inositol polyphosphate 5-phosphatase OCRL: Difference between revisions
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The membrane lipids phosphatidylinositol can be phosphorylated at positions 3, 4 and 5 of the inositol ring, which generates eight possible species called phosphoinositides. OCRL1 is one of the phosphatases that removes phosphate groups from specific positions of the inositol ring - OCRL1 selectively acts as a 5-phosphatase. Phosphatidylinositols together with proteins of the Rab family typically have their distinct subcellular localization, and they are both an integral part of the recognition machinery of membrane compartments, which regulates membrane trafficking between organelles. Rab GTPases regulate membrane trafficking through interactions with various effectors, one of them being the phosphatase OCRL1.<ref name="main">PMID: 21378754</ref> | The membrane lipids phosphatidylinositol can be phosphorylated at positions 3, 4 and 5 of the inositol ring, which generates eight possible species called phosphoinositides. OCRL1 is one of the phosphatases that removes phosphate groups from specific positions of the inositol ring - OCRL1 selectively acts as a 5-phosphatase. Phosphatidylinositols together with proteins of the Rab family typically have their distinct subcellular localization, and they are both an integral part of the recognition machinery of membrane compartments, which regulates membrane trafficking between organelles. Rab GTPases regulate membrane trafficking through interactions with various effectors, one of them being the phosphatase OCRL1.<ref name="main">PMID: 21378754</ref> | ||
OCRL1 shows multiple binding sites for clathrin coat components (clathrin heavy chain and AP2 clathrin adaptor) so it seems to have a role in clathrin-mediated endocytosis. The two motifs involved in clathrin binding are located in the PH and Rho-GAP-like domains.<ref name="role"/> The 8 AA insertion in the longer isoform A enhances the interaction with | OCRL1 shows multiple binding sites for clathrin coat components (clathrin heavy chain and AP2 clathrin adaptor) so it seems to have a role in clathrin-mediated endocytosis because it is recruited to clathrin‐coated pits at the later stages of the vesicle formation process.<ref>PMID: 26351914</ref>. The two motifs involved in clathrin binding are located in the PH and Rho-GAP-like domains.<ref name="role"/> The 8 AA insertion in the longer isoform A enhances the interaction with clathrins.<ref name="isoform">PMID: 19211563</ref> | ||
OCRL1 phosphatase activity prevents ectopic accumulation of PtdIns(4,5)P2 (and possibly PtdIns(3,4,5)P3) on intracellular membrane. This helps maintaining phosphoinositide spatial segregation and homeostasis within the cell.<ref name="role"/> | OCRL1 phosphatase activity prevents ectopic accumulation of PtdIns(4,5)P2 (and possibly PtdIns(3,4,5)P3) on intracellular membrane. This helps maintaining phosphoinositide spatial segregation and homeostasis within the cell.<ref name="role"/> | ||