| First Author | DeLalio LJ | Year | 2019 |
| Journal | J Biol Chem | Volume | 294 |
| Issue | 17 | Pages | 6940-6956 |
| PubMed ID | 30814251 | Mgi Jnum | J:277894 |
| Mgi Id | MGI:6324101 | Doi | 10.1074/jbc.RA118.006982 |
| Citation | DeLalio LJ, et al. (2019) Constitutive SRC-mediated phosphorylation of pannexin 1 at tyrosine 198 occurs at the plasma membrane. J Biol Chem 294(17):6940-6956 |
| abstractText | Pannexin 1 (PANX1)-mediated ATP release in vascular smooth muscle coordinates alpha1-adrenergic receptor (alpha1-AR) vasoconstriction and blood pressure homeostasis. We recently identified amino acids 198-200 (YLK) on the PANX1 intracellular loop that are critical for alpha1-AR-mediated vasoconstriction and PANX1 channel function. We report herein that the YLK motif is contained within an SRC homology 2 domain and is directly phosphorylated by SRC proto-oncogene, nonreceptor tyrosine kinase (SRC) at Tyr(198) We demonstrate that PANX1-mediated ATP release occurs independently of intracellular calcium but is sensitive to SRC family kinase (SFK) inhibition, suggestive of channel regulation by tyrosine phosphorylation. Using a PANX1 Tyr(198)-specific antibody, SFK inhibitors, SRC knockdown, temperature-dependent SRC cells, and kinase assays, we found that PANX1-mediated ATP release and vasoconstriction involves constitutive phosphorylation of PANX1 Tyr(198) by SRC. We specifically detected SRC-mediated Tyr(198) phosphorylation at the plasma membrane and observed that it is not enhanced or induced by alpha1-AR activation. Last, we show that PANX1 immunostaining is enriched in the smooth muscle layer of arteries from hypertensive humans and that Tyr(198) phosphorylation is detectable in these samples, indicative of a role for membrane-associated PANX1 in small arteries of hypertensive humans. Our discovery adds insight into the regulation of PANX1 by post-translational modifications and connects a significant purinergic vasoconstriction pathway with a previously identified, yet unexplored, tyrosine kinase-based alpha1-AR constriction mechanism. This work implicates SRC-mediated PANX1 function in normal vascular hemodynamics and suggests that Tyr(198)-phosphorylated PANX1 is involved in hypertensive vascular pathology. |
