The 5-phosphatase OCRL mediates retrograde transport of the mannose 6-phosphate receptor by regulating a Rac1-cofilin signalling module.
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The 5-phosphatase OCRL mediates retrograde transport of the mannose 6-phosphate receptor by regulating a Rac1-cofilin signalling module. / van Rahden, Vanessa; Brand, Kristina; Najm, Juliane; Heeren, Jörg; Heeren, Joerg; Braulke, Thomas; Kutsche, Kerstin; Kutsche, Kerstin.
In: HUM MOL GENET, Vol. 21, No. 23, 23, 2012, p. 5019-5038.Research output: SCORING: Contribution to journal › SCORING: Journal article › Research › peer-review
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T1 - The 5-phosphatase OCRL mediates retrograde transport of the mannose 6-phosphate receptor by regulating a Rac1-cofilin signalling module.
AU - van Rahden, Vanessa
AU - Brand, Kristina
AU - Najm, Juliane
AU - Heeren, Jörg
AU - Heeren, Joerg
AU - Braulke, Thomas
AU - Kutsche, Kerstin
AU - Kutsche, Kerstin
PY - 2012
Y1 - 2012
N2 - Mutations in the OCRL gene encoding the phosphatidylinositol 4,5-bisphosphate (PI(4,5)P(2)) 5-phosphatase OCRL cause Lowe syndrome (LS), which is characterized by intellectual disability, cataracts and selective proximal tubulopathy. OCRL localizes membrane-bound compartments and is implicated in intracellular transport. Comprehensive analysis of clathrin-mediated endocytosis in fibroblasts of patients with LS did not reveal any difference in trafficking of epidermal growth factor, low density lipoprotein or transferrin, compared with normal fibroblasts. However, LS fibroblasts displayed reduced mannose 6-phosphate receptor (MPR)-mediated re-uptake of the lysosomal enzyme arylsulfatase B. In addition, endosome-to-trans Golgi network (TGN) transport of MPRs was decreased significantly, leading to higher levels of cell surface MPRs and their enrichment in enlarged, retromer-positive endosomes in OCRL-depleted HeLa cells. In line with the higher steady-state concentration of MPRs in the endosomal compartment in equilibrium with the cell surface, anterograde transport of the lysosomal enzyme, cathepsin D was impaired. Wild-type OCRL counteracted accumulation of MPR in endosomes in an activity-dependent manner, suggesting that PI(4,5)P(2) modulates the activity state of proteins regulated by this phosphoinositide. Indeed, we detected an increased amount of the inactive, phosphorylated form of cofilin and lower levels of the active form of PAK3 upon OCRL depletion. Levels of active Rac1 and RhoA were reduced or enhanced, respectively. Overexpression of Rac1 rescued both enhanced levels of phosphorylated cofilin and MPR accumulation in enlarged endosomes. Our data suggest that PI(4,5)P(2) dephosphorylation through OCRL regulates a Rac1-cofilin signalling cascade implicated in MPR trafficking from endosomes to the TGN.
AB - Mutations in the OCRL gene encoding the phosphatidylinositol 4,5-bisphosphate (PI(4,5)P(2)) 5-phosphatase OCRL cause Lowe syndrome (LS), which is characterized by intellectual disability, cataracts and selective proximal tubulopathy. OCRL localizes membrane-bound compartments and is implicated in intracellular transport. Comprehensive analysis of clathrin-mediated endocytosis in fibroblasts of patients with LS did not reveal any difference in trafficking of epidermal growth factor, low density lipoprotein or transferrin, compared with normal fibroblasts. However, LS fibroblasts displayed reduced mannose 6-phosphate receptor (MPR)-mediated re-uptake of the lysosomal enzyme arylsulfatase B. In addition, endosome-to-trans Golgi network (TGN) transport of MPRs was decreased significantly, leading to higher levels of cell surface MPRs and their enrichment in enlarged, retromer-positive endosomes in OCRL-depleted HeLa cells. In line with the higher steady-state concentration of MPRs in the endosomal compartment in equilibrium with the cell surface, anterograde transport of the lysosomal enzyme, cathepsin D was impaired. Wild-type OCRL counteracted accumulation of MPR in endosomes in an activity-dependent manner, suggesting that PI(4,5)P(2) modulates the activity state of proteins regulated by this phosphoinositide. Indeed, we detected an increased amount of the inactive, phosphorylated form of cofilin and lower levels of the active form of PAK3 upon OCRL depletion. Levels of active Rac1 and RhoA were reduced or enhanced, respectively. Overexpression of Rac1 rescued both enhanced levels of phosphorylated cofilin and MPR accumulation in enlarged endosomes. Our data suggest that PI(4,5)P(2) dephosphorylation through OCRL regulates a Rac1-cofilin signalling cascade implicated in MPR trafficking from endosomes to the TGN.
KW - Humans
KW - Protein Transport
KW - Hela Cells
KW - Phosphorylation
KW - HEK293 Cells
KW - Signal Transduction
KW - RNA Interference
KW - Fibroblasts/metabolism
KW - Endosomes/metabolism
KW - Actin Depolymerizing Factors/metabolism
KW - Arylsulfonates/metabolism
KW - Cathepsin D/metabolism
KW - Lysosomal-Associated Membrane Protein 1/metabolism
KW - Oculocerebrorenal Syndrome/genetics/metabolism
KW - Phosphoric Monoester Hydrolases/genetics/metabolism
KW - Receptor, IGF Type 2/metabolism
KW - p21-Activated Kinases/metabolism
KW - rac1 GTP-Binding Protein/genetics/metabolism
KW - rhoA GTP-Binding Protein/metabolism
KW - trans-Golgi Network/metabolism
KW - Humans
KW - Protein Transport
KW - Hela Cells
KW - Phosphorylation
KW - HEK293 Cells
KW - Signal Transduction
KW - RNA Interference
KW - Fibroblasts/metabolism
KW - Endosomes/metabolism
KW - Actin Depolymerizing Factors/metabolism
KW - Arylsulfonates/metabolism
KW - Cathepsin D/metabolism
KW - Lysosomal-Associated Membrane Protein 1/metabolism
KW - Oculocerebrorenal Syndrome/genetics/metabolism
KW - Phosphoric Monoester Hydrolases/genetics/metabolism
KW - Receptor, IGF Type 2/metabolism
KW - p21-Activated Kinases/metabolism
KW - rac1 GTP-Binding Protein/genetics/metabolism
KW - rhoA GTP-Binding Protein/metabolism
KW - trans-Golgi Network/metabolism
M3 - SCORING: Journal article
VL - 21
SP - 5019
EP - 5038
JO - HUM MOL GENET
JF - HUM MOL GENET
SN - 0964-6906
IS - 23
M1 - 23
ER -
