The Laminin-Induced Phosphorylation of PKC δ Regulates AQP4 Distribution and Water Permeability in Rat Astrocytes.

The Laminin-Induced Phosphorylation of PKCδ Regulates AQP4 Distribution and Water Permeability in Rat Astrocytes. Cell Mol Neurobiol. 2020 Aug 26;: Authors: Noël G, Tham DKL, Guadagno E, MacVicar B, Moukhles H Abstract In astrocytes, the water-permeable channel aquaporin-4 (AQP4) is concentrated at the endfeet that abut the blood vessels of the brain. The asymmetric distribution of this channel is dependent on the function of dystroglycan (DG), a co-expressed laminin receptor, and its associated protein complex. We have demonstrated that the addition of laminin to astrocytes in culture causes the clustering of AQP4, DG, and lipid rafts. The last, in particular, have been associated with the initiation of cell signaling. As laminin binding to DG in muscle cells can induce the tyrosine phosphorylation of syntrophin and laminin requires tyrosine kinases for acetylcholine receptor clustering in myotubes, we asked if signal transduction might also be involved in AQP4 clustering in astrocytes. We analyzed the timecourse of AQP4, DG, and monosialotetrahexosylganglioside (GM1) clustering in primary cultures of rat astrocytes following the addition of laminin, and determined that the clustering of DG precedes that of AQP4 and GM1. We also showed that laminin induces the formation of phosphotyrosine-rich clusters and that the tyrosine kinase inhibitor, genistein, disrupts the laminin-induced clustering of both β-DG and AQP4. Using the Kinex...
Source: Cellular and Molecular Neurobiology - Category: Cytology Authors: Tags: Cell Mol Neurobiol Source Type: research