Effect of acute acid-base disturbances on the phosphorylation of phospholipase C-γ1 and Erk1/2 in the renal proximal tubule.
Effect of acute acid-base disturbances on the phosphorylation of phospholipase C-γ1 and Erk1/2 in the renal proximal tubule.
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DOI：
10.14814/phy2.12280
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发表时间：
2015-03
影响因子：
2.5
通讯作者：
Boron WF
中科院分区：
文献类型：
--
作者：
Skelton LA;Boron WF
肾近端小管 (PT) 通过将 H+ 分泌到肾小管腔内，在全身 pH 稳态中发挥重要作用。先前的工作表明，PT 通过适当改变被 ErbB 抑制剂 PD168393 阻断的 H+ 分泌反应，或通过消除通过 AT1 血管紧张素受体的信号传导来响应 [CO2] 和 [] 的基底外侧变化。在本研究中，我们分析了 ErbBs 和 AT1 的三个下游靶标的磷酸化：磷脂酶 C-γ1 (PLC-γ1)、细胞外调节激酶 1 (Erk1) 和 Erk2。我们将兔 PT 悬浮液暴露于我们的对照 (Ctrl) 条件（5% CO2，22 mmol/L，pH 7.40）或模拟酸碱干扰的几种条件之一中 5 分钟和 20 分钟。我们发现每种干扰都会在三种酶中产生特征性的磷酸化模式。例如，20 分钟时呼吸性酸中毒（[CO2] 升高，[] 正常）会降低 PLC-γ1 酪氨酸 783 处的磷酸化（相对于 Ctrl）。代谢性酸中毒（[CO2] 正常，[] 降低）持续 5 分钟会增加 Erk1 磷酸化 (p-Erk1)，但不会增加 p-Erk2，而代谢性碱中毒（[CO2] 正常，[] 升高）持续 5 分钟会降低 p-Erk1 和 p-Erk2。在 CO2/ 存在的情况下，PD168393 仅阻断八种诱导的磷酸化降低中的两种。在两种干扰对磷酸化没有显着影响的情况下，PD168393 暴露减少，而在另外两种情况下，PD168393 暴露增加。这些药物作用让我们深入了解 PD168393 敏感激酶的作用。我们的结果表明，PT 中的 PLC-γ1.pY783、p-Erk1 和 p-Erk2 响应急性酸碱紊乱而以特有的方式发生变化，因此可能有助于酸碱信号的转导。
The renal proximal tubule (PT) plays a major role in whole-body pH homeostasis by secreting H+ into the tubule lumen. Previous work demonstrated that PTs respond to basolateral changes in [CO2] and [] by appropriately altering H+ secretion—responses blocked by the ErbB inhibitor PD168393, or by eliminating signaling through AT1 angiotensin receptors. In the present study, we analyze phosphorylation of three downstream targets of both ErbBs and AT1: phospholipase C-γ1 (PLC-γ1), extracellular-regulated kinase 1 (Erk1), and Erk2. We expose rabbit PT suspensions for 5 and 20 min to our control (Ctrl) condition (5% CO2, 22 mmol/L , pH 7.40) or one of several conditions that mimic acid-base disturbances. We found that each disturbance produces characteristic phosphorylation patterns in the three enzymes. For example, respiratory acidosis (elevated [CO2], normal []) at 20 min decreases PLC-γ1 phosphorylation at tyrosine-783 (relative to Ctrl). Metabolic acidosis (normal [CO2], decreased []) for 5 min increases Erk1 phosphorylation (p-Erk1) but not p-Erk2, whereas metabolic alkalosis (normal [CO2], elevated []) for 5 min decreases p-Erk1 and p-Erk2. In the presence of CO2/, PD168393 blocks only two of eight induced decreases in phosphorylation. In two cases in which disturbances have no remarkable effects on phosphorylation, PD168393 unmasks decreases and in two others, increases. These drug effects provide insight into the roles of PD168393-sensitive kinases. Our results indicate that PLC-γ1.pY783, p-Erk1, and p-Erk2 in the PT change in characteristic ways in response to acute acid-base disturbances, and thus presumably contribute to the transduction of acid-base signals.