Global and endothelial loss of PTP-PEST (also known as PTPN12) is associated with impaired cardiovascular development and embryonic lethality. Although hypoxia is implicated in vascular remodelling and angiogenesis, its effect on PTP-PEST remains unexplored. Here we report that hypoxia (1% oxygen) increases protein levels and catalytic activity of PTP-PEST in primary endothelial cells. Immunoprecipitation followed by mass spectrometry revealed that α subunits of AMPK (α₁ and α₂, encoded by PRKAA1 and PRKAA2, respectively) interact with PTP-PEST under normoxia but not in hypoxia. Co-immunoprecipitation experiments confirmed this observation and determined that AMPK α subunits interact with the catalytic domain of PTP-PEST. Knockdown of PTP-PEST abrogated hypoxia-mediated tyrosine dephosphorylation and activation of AMPK (Thr¹⁷² phosphorylation). Absence of PTP-PEST also blocked hypoxia-induced autophagy (LC3 degradation and puncta formation), which was rescued by the AMPK activator metformin (500 µM). Because endothelial autophagy is a prerequisite for angiogenesis, knockdown of PTP-PEST also attenuated endothelial cell migration and capillary tube formation, with autophagy inducer rapamycin (200 nM) rescuing angiogenesis. In conclusion, this work identifies for the first time that PTP-PEST is a regulator of hypoxia-induced AMPK activation and endothelial autophagy to promote angiogenesis.

PTP-PEST（也称为 PTPN12）的整体和内皮细胞损失与心血管发育受损和胚胎致死有关。尽管缺氧与血管重塑和血管生成有关，但其对 PTP-PEST 的影响仍未被探索。在这里，我们报告缺氧（1% 氧气）会增加原代内皮细胞中 PTP-PEST 的蛋白质水平和催化活性。免疫沉淀和质谱分析显示，AMPK 的 α 亚基（α ₁和 α _{2 ，分别由}PRKAA1和PRKAA2编码）在常氧条件下与 PTP-PEST 相互作用，但在缺氧条件下则不然。免疫共沉淀实验证实了这一观察结果，并确定 AMPK α 亚基与 PTP-PEST 的催化结构域相互作用。PTP-PEST 的敲除消除了缺氧介导的酪氨酸去磷酸化和 AMPK 的激活（Thr ¹⁷²磷酸化）。PTP-PEST 的缺失也会阻断缺氧诱导的自噬（LC3 降解和斑点形成），而 AMPK 激活剂二甲双胍 (500 µM) 可以挽救这种自噬。由于内皮自噬是血管生成的先决条件，PTP-PEST 的敲低也会减弱内皮细胞迁移和毛细管形成，而自噬诱导剂雷帕霉素 (200 nM) 则可挽救血管生成。总之，这项工作首次确定 PTP-PEST 是缺氧诱导的 AMPK 激活和内皮自噬的调节剂，以促进血管生成。