AMPKα2 activation by an energy-independent signal ensures chromosomal stability during mitosis

Abstract

Summary AMP-activated protein kinase (AMPK) senses energy status and impacts energy-consuming events by initiating metabolism regulatory signals in cells. Accumulating evidences suggest a role of AMPK in mitosis regulation, but the mechanism of mitotic AMPK activation and function remains elusive. Here we report that AMPKα2, but not AMPKα1, is sequentially phosphorylated and activated by CDK1 and PLK1, which enables AMPKα2 to accurately guide chromosome segregation in mitosis. Phosphorylation at Thr485 by activated CDK1-Cyclin B1 brings the ST-stretch of AMPKα2 to the Polo box domain of PLK1 for subsequent Thr172 phosphorylation by PLK1. Inserting of the AMPKα2 ST-stretch into AMPKα1, which lacks the ST-stretch, can correct mitotic chromosome segregation defects in AMPKα2-depleted cells. These findings uncovered a specific signaling cascade integrating sequential phosphorylation by CDK1 and PLK1 of AMPKα2 with mitosis to maintain genomic stability, thus defining an isoform-specific AMPKα2 function, which will facilitate future research on energy sensing in mitosis.

PRL stimulates mitotic errors by suppressing kinetochore-localized activation of AMPK during mitosis

“…spindle poles, midzones, and midbodies, through prophase to cytokinesis(Vazquez-Martin et al, 2011;Lu et al, 2021). Our observations confirmed P-AMPK localization, but additional dot-like signals of P-AMPK at the chromosomes in mitotic cells from prometaphase to anaphase were also observed (Fig.4A).…”

“…Such kinetochore-localized P-AMPK signals were also observed in HeLa cells, although the signals were mostly observed during prometaphase (Supplementary Fig.4). Moreover, a similar localization of P-AMPK at the kinetochore has been reported in mouse intestinal epithelial cells and culture cell lines such as HeLa and U2OS(Lu et al, 2021;Wei et al, 2012). To investigate whether PRL3 expression affects the localization of P-AMPK signals, cells were stained for P-AMPK (Fig4B).…”

“…In this study, we showed that PRL overexpression specifically inhibits the recruitment of P-AMPK at kinetochore during mitosis without affecting its localization to other mitotic structures. Although several studies have reported that P-AMPK localizes at the kinetochore (Lu et al, 2021;Wei et al, 2012), its functional importance and localization mechanism remain largely unknown. Our observations demonstrated the importance of PRL in this process and revealed the events of mitotic errors associated with AMPK function.…”

“…In addition, phosphorylated AMPK (P-AMPK) proteins have been reported to localize to various mitotic structures such as spindle poles, midzones, and midbodies, and kinetochores during mitosis (Vazquez-Martin et al, 2011;Lu et al, 2021). Studies using AMPK-knockdown or knockout mammalian cultured cells and Ampk-null Drosophila melanogaster mutants have revealed a role of AMPK in mitosis, since they have various mitotic defects, such as mitotic delay, chromosome misalignment, spindle misorientation, and chromosome missegregation, such as lagging or polyploid chromosomes (Lu et al, 2021;Thaiparambil et al, 2012;Lee et al, 2007;Stauffer et al, 2019). Mitotic errors are often associated with aneuploidy, defined as the loss or gain of chromosomes, which is found in approximately 90% of tumors and has been proposed to drive cancer progression (Ben-David et al, 2020; Vasudevan et al, 2021).…”

Resveratrol-induced Sirt1 phosphorylation by LKB1 mediates mitochondrial metabolism

“…The background fluorescence was determined by measuring the fluorescence intensity in the absence of substrate and subtracted from the experiments. Km and kcat values were calculated by the Michaelis-Menten equation as previously reported (83).…”