Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, 10901 N. Torrey Pines Road, La Jolla, CA 92037, USA.
Université de Paris, Institut Cochin, CNRS UMR8104, INSERM U1016, Paris 75014, France.
Cell Signal. 2022 Jan;89:110170. doi: 10.1016/j.cellsig.2021.110170. Epub 2021 Oct 18.
Autophagy is a multi-step process regulated in part by AMP-activated protein kinase (AMPK). Phosphorylation of threonine 172 on the AMPK α-subunit enhances AMPK kinase activity, resulting in activation of downstream signaling. Integrin-mediated cell adhesion activates Src/ Focal Adhesion Kinase (FAK) signaling complex, which regulates multiple cellular processes including cell survival. We show here that Src signaling leads to direct phosphorylation of the AMPK-α subunit on a novel site, tyrosine 179, resulting in suppression of AMPK-T172 phosphorylation and autophagy upon integrin-mediated cell adhesion. By using chemical inhibitors, genetic cell models and targeted mutagenesis, we confirm an important role for Src and FAK in suppressing AMPK signaling and autophagy induced by various additional stimuli, including glucose starvation. Furthermore, we found that autophagy suppression by hydroxychloroquine promotes apoptosis in a cancer cell model that had been treated with Src inhibitors. Our findings reveal a link between the Src/ FAK complex and AMPK/ autophagy regulation, which may play an important role in the maintenance of normal cellular homeostasis and tumor progression.
自噬是一个由 AMP 激活的蛋白激酶（AMPK）调控的多步骤过程。AMPKα亚基上苏氨酸 172 的磷酸化增强了 AMPK 激酶活性，导致下游信号的激活。整合素介导的细胞黏附激活Src/黏着斑激酶（FAK）信号复合物，调节包括细胞存活在内的多种细胞过程。我们在此表明，Src 信号导致 AMPK-α亚基在一个新的位点酪氨酸 179 上的直接磷酸化，导致 AMPK-T172 磷酸化和整合素介导的细胞黏附时的自噬受到抑制。通过使用化学抑制剂、遗传细胞模型和靶向突变，我们证实 Src 和 FAK 在抑制 AMPK 信号和各种其他刺激（包括葡萄糖饥饿）诱导的自噬中起着重要作用。此外，我们发现，Src 抑制剂处理后的癌细胞模型中，羟氯喹抑制自噬可促进细胞凋亡。我们的发现揭示了 Src/FAK 复合物与 AMPK/自噬调节之间的联系，这可能在维持正常细胞内稳态和肿瘤进展中起着重要作用。
