Lysophosphatidic acid stimulation of NHE3 exocytosis in polarized epithelial cells occurs with release from NHERF2 via ERK-PLC-PKCδ signaling
| Autor: | Daniel M. Raben, C. Ming Tse, Boyoung Cha, Jianbo Yang, Rafiquel Sarker, Olga Kovbasnjuk, Tian-e Chen, Mark Donowitz |
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| Rok vydání: | 2014 |
| Předmět: |
rho GTP-Binding Proteins
MAPK/ERK pathway Sodium-Hydrogen Exchangers Time Factors Brush border Phosphodiesterase Inhibitors Physiology Antiporter Biology Transfection Exocytosis Cell Line Kidney Tubules Proximal chemistry.chemical_compound Lysophosphatidic acid medicine Animals Humans Receptors Lysophosphatidic Acid Extracellular Signal-Regulated MAP Kinases Protein Kinase Inhibitors rho-Associated Kinases Microvilli Sodium-Hydrogen Exchanger 3 urogenital system Epithelial Cells Opossums Articles Cell Biology Phosphoproteins Microvillus Cell biology ErbB Receptors Protein Kinase C-delta Protein Transport Sodium–hydrogen antiporter medicine.anatomical_structure chemistry Type C Phospholipases Calcium RNA Interference Rabbits Lysophospholipids Signal transduction Signal Transduction |
| Zdroj: | American Journal of Physiology-Cell Physiology. 307:C55-C65 |
| ISSN: | 1522-1563 0363-6143 |
| Popis: | The Na+/H+ exchanger 3 (NHE3) is a brush border (BB) Na+/H+ antiporter that accounts for the majority of physiologic small intestinal and renal Na+ absorption. It is regulated physiologically and in disease via changes in endocytosis/exocytosis. Paradoxically, NHE3 is fixed to the microvillar (MV) actin cytoskeleton and has little basal mobility. This fixation requires NHE3 binding to the multi-PDZ domain scaffold proteins Na+/H+ exchanger regulatory factor (NHERF)1 and NHERF2 and to ezrin. Coordinated release of NHE3 from the MV cytoskeleton has been demonstrated during both stimulation and inhibition of NHE3. However, the signaling molecules involved in coordinating NHE3 trafficking and cytoskeletal association have not been identified. This question was addressed by studying lysophosphatidic acid (LPA) stimulation of NHE3 in polarized renal proximal tubule opossum kidney (OK) cells that occurs via apical LPA5 receptors and is NHERF2 dependent and mediated by epidermal growth factor receptor (EGFR), Rho/Rho-associated kinase (ROCK), and ERK. NHE3 activity was determined by BCECF/fluorometry and NHE3 microvillar mobility by FRAP/confocal microscopy using NHE3-EGFP. Apical LPA (3 μM)/LPA5R stimulated NHE3 activity, increased NHE3 mobility, and decreased the NHE3/NHERF2 association. The LPA stimulation of NHE3 was also PKCδ dependent. PKCδ was necessary for LPA stimulation of NHE3 mobility and NHE3/NHERF2 association. Moreover, the LPA-induced translocation to the membrane of PKCδ was both ERK and phospholipase C dependent with ERK acting upstream of PLC. We conclude that LPA stimulation of NHE3 exocytosis includes a signaling pathway that regulates fixation of NHE3 to the MV cytoskeleton. This involves a signaling module consisting of ERK-PLC-PKCδ, which dynamically and reversibly releases NHE3 from NHERF2 to contribute to the changes in NHE3 MV mobility. |
| Databáze: | OpenAIRE |
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