SUMO1 modification of PKD2 channels regulates arterial contractility

Abstract

PKD2 (polycystin-2, TRPP1) channels are expressed in a wide variety of cell types and can regulate functions, including cell division and contraction. Whether posttranslational modification of PKD2 modifies channel properties is unclear. Similarly uncertain are signaling mechanisms that regulate PKD2 channels in arterial smooth muscle cells (myocytes). Here, by studying inducible, cell-specificPkd2knockout mice, we discovered that PKD2 channels are modified by SUMO1 (small ubiquitin-like modifier 1) protein in myocytes of resistance-size arteries. At physiological intravascular pressures, PKD2 exists in approximately equal proportions as either nonsumoylated (PKD2) or triple SUMO1-modifed (SUMO-PKD2) proteins. SUMO-PKD2 recycles, whereas unmodified PKD2 is surface-resident. Intravascular pressure activates voltage-dependent Ca2+influx that stimulates the return of internalized SUMO-PKD2 channels to the plasma membrane. In contrast, a reduction in intravascular pressure, membrane hyperpolarization, or inhibition of Ca2+influx leads to lysosomal degradation of internalized SUMO-PKD2 protein, which reduces surface channel abundance. Through this sumoylation-dependent mechanism, intravascular pressure regulates the surface density of SUMO-PKD2−mediated Na+currents (INa) in myocytes to control arterial contractility. We also demonstrate that intravascular pressure activates SUMO-PKD2, not PKD2, channels, as desumoylation leads to loss of INaactivation in myocytes and vasodilation. In summary, this study reveals that PKD2 channels undergo posttranslational modification by SUMO1, which enables physiological regulation of their surface abundance and pressure-mediated activation in myocytes and thus control of arterial contractility.

Empagliflozin Relaxes Resistance Mesenteric Arteries by Stimulating Multiple Smooth Muscle Cell Voltage-Gated K+ (KV) Channels

“…To assess the role of endothelium further, we compared empagliflozin-induced vasodilation in endothelium-intact and endothelium-denuded mesenteric arteries. Endothelium denudation was performed by slowly passing air bubbles through the vessel lumen and confirmed as described by others previously [ 39 , 40 , 41 ]. Briefly, we applied 1 µM acetylcholine (ACh) to endothelium-intact and endothelium-denuded arterial segments that had been preconstricted with 1 µM PE.…”

“…The application of 1 µM sodium nitroprusside (SNP), a NO donor, completely reversed PE constriction in both endothelium-intact and endothelium-denuded arteries ( Figure 5 A,B), suggesting that endothelium denudation does not affect smooth muscle responses to NO. Since ACh-induced vasodilation is primarily mediated by endothelial NO production, selective loss of ACh-evoked vasodilation demonstrates successful endothelium denudation [ 39 , 40 , 41 ]. We then compared empagliflozin responses in endothelium-intact and endothelium-denuded arteries.…”

“…Third and fourth order branches of mesenteric arteries (150–250 µm) were dissected cleaned of adventitial tissue in ice-cold PSS. Cleaned arterial branches were cut into 1–2 mm long segments that were kept in ice-cold PSS until cannulated for pressure myography [ 39 , 40 , 41 , 57 ].…”

Age‐dependent decrease in TRPM4 channel expression but not trafficking alters urinary bladder smooth muscle contractility

“…To further investigate if the decrease in total TRPM4 protein changed the cellular localization of the channel in UBSM‐A and UBSM‐J, we used the surface biotinylation procedure. Cell surface biotinylation of smooth muscle tissue has been well characterized for arterial smooth muscle previously (Hasan et al, 2019; Leo et al, 2015). The same protocol with minor adjustments was used to examine TRPM4 channel localization in UBSM‐J and UBSM‐A.…”

“…Ion channels that determine smooth muscle excitability need to be present on the plasma membrane to exert their regulatory control. Cellular localization analyses of ion channel subunits have been done previously in arterial smooth muscle (Hasan et al, 2019; Leo & Jaggar, 2017). However, there are no reports so far on UBSM ion channel trafficking.…”