PKC-dependent coupling of calcium permeation through transient receptor potential canonical 3 (TRPC3) to calcineurin signaling in HL-1 myocytes

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 108; no. 26; pp. 10556 - 10561
• Main Authors: Poteser, Michael, Schleifer, Hannes, Lichtenegger, Michaela, Schernthaner, Michaela, Stockner, Thomas, Kappe, C. Oliver, Glasnov, Toma N, Romanin, Christoph, Groschner, Klaus
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 28.06.2011; National Acad Sciences
• Subjects: Animals; Antibodies; Biological Sciences; Calcineurin; Calcineurin - metabolism; Calcium; Calcium - metabolism; Calcium channels (voltage-gated); Calcium influx; Calcium permeability; calcium signaling; Calcium signalling; Cell Line; Cell lines; Cells; Channel pores; Endothelial cells; Fluorescence; Gene expression; Heart; HEK293 cells; Humans; Ion Transport; Mice; Mutation; Myocardium - cytology; Myocardium - enzymology; Myocardium - metabolism; Myocytes; NF-AT protein; NFATC Transcription Factors - metabolism; Permeability; Phosphorylation; Point mutation; Protein kinase C; Protein Kinase C - metabolism; Receptors; Signal Transduction; Statistical significance; T-lymphocytes; Transcription; transcription (genetics); Transcription factors; transient receptor potential proteins; Translocation; TRPC cation channels; TRPC Cation Channels - metabolism
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.1106183108

Cardiac transient receptor potential canonical (TRPC) channels are crucial upstream components of Ca²⁺/calcineurin/nuclear factor of activated T cells (NFAT) signaling, thereby controlling cardiac transcriptional programs. The linkage between TRPC-mediated Ca²⁺ signals and NFAT activity is still incompletely understood. TRPC conductances may govern calcineurin activity and NFAT translocation by supplying Ca²⁺ either directly through the TRPC pore into a regulatory microdomain or indirectly via promotion of voltage-dependent Ca²⁺ entry. Here, we show that a point mutation in the TRPC3 selectivity filter (E630Q), which disrupts Ca²⁺ permeability but preserves monovalent permeation, abrogates agonist-induced NFAT signaling in HEK293 cells as well as in murine HL-1 atrial myocytes. The E630Q mutation fully retains the ability to convert phospholipase C-linked stimuli into L-type (CaV1.2) channel-mediated Ca²⁺ entry in HL-1 cells, thereby generating a dihydropyridine-sensitive Ca²⁺ signal that is isolated from the NFAT pathway. Prevention of PKC-dependent modulation of TRPC3 by either inhibition of cellular kinase activity or mutation of a critical phosphorylation site in TRPC3 (T573A), which disrupts targeting of calcineurin into the channel complex, converts cardiac TRPC3-mediated Ca²⁺ signaling into a transcriptionally silent mode. Thus, we demonstrate a dichotomy of TRPC-mediated Ca²⁺ signaling in the heart constituting two distinct pathways that are differentially linked to gene transcription. Coupling of TRPC3 activity to NFAT translocation requires microdomain Ca²⁺ signaling by PKC-modified TRPC3 complexes. Our results identify TRPC3 as a pivotal signaling gateway in Ca²⁺-dependent control of cardiac gene expression.