Palmitoylation regulates cellular distribution of and transmembrane Ca flux through TrpM7. (September 2022)

• Record Type: Journal Article
• Authors: Gao, Xing; Kuo, Chien-Wen; Main, Alice; Brown, Elaine; Rios, Francisco J.; Camargo, Livia De Lucca; Mary, Sheon; Wypijewski, Krzysztof; Gök, Caglar; Touyz, Rhian M.; Fuller, William
• Is Part Of: Cell calcium. Volume 106(2022)
• Publication Date: 2022-09
• Subjects: Acylation -- Lipidation -- Magnesium -- Zinc -- Calcium -- Divalent cation transport -- Trp channels -- Palmitoyl acyl transferase; Calcium -- Metabolism -- Periodicals; Vertebrates -- Physiology -- Periodicals; Calcium -- Physiological effect -- Periodicals; Cell physiology -- Periodicals; Calcium in the body -- Periodicals; 572.516
• DOI: 10.1016/j.ceca.2022.102639
• Languages: English
• ISSNs: 0143-4160

Abstract

Highlights: The 'chanzyme' TrpM7 is palmitoylated at a cluster of cysteines near its Trp domain. Palmitoylation controls TrpM7 trafficking and subcellular distribution. TrpM7 mediated Ca influx is substantially reduced when it is not palmitoylated. The closely related protein TrpM6 is also palmitoylated near its Trp domain. Abstract: The bifunctional cation channel/kinase TrpM7 is ubiquitously expressed and regulates embryonic development and pathogenesis of several common diseases. The TrpM7 integral membrane ion channel domain regulates transmembrane movement of divalent cations, and its kinase domain controls gene expression via histone phosphorylation. Mechanisms regulating TrpM7 are elusive. It exists in two populations in the cell: at the cell surface where it controls divalent cation fluxes, and in intracellular vesicles where it controls zinc uptake and release. Here we report that TrpM7 is palmitoylated at a cluster of cysteines at the C terminal end of its Trp domain. Palmitoylation controls the exit of TrpM7 from the endoplasmic reticulum and the distribution of TrpM7 between cell surface and intracellular pools. Using the Retention Using Selective Hooks (RUSH) system, we demonstrate that palmitoylated TrpM7 traffics from the Golgi to the surface membrane whereas non-palmitoylated TrpM7 is sequestered in intracellular vesicles. We identify the Golgi-resident enzyme zDHHC17 and surface membrane-resident enzyme zDHHC5 as responsible for palmitoylating TrpM7 and find that TrpM7-mediated transmembrane calcium uptake is significantly reduced when TrpM7 is not palmitoylated. The closely related channel/kinase TrpM6 is also palmitoylated on the C terminal side of its Trp domain. Our findings demonstrate that palmitoylation controls ion channel activity of TrpM7 and that TrpM7 trafficking is dependant on its palmitoylation. We define a new mechanism for post translational modification and regulation of TrpM7 and other Trps. Graphical abstract: Image, graphical abstract