Exercise and Nutrition Research Program, Mary MacKillop Institute for Health Research, Australian Catholic University, Level 5, 215 Spring Street, Melbourne, VIC 3000, Australia.
St. Vincent's Institute of Medical Research, Department of Medicine, University of Melbourne, 9 Princes Street, Fitzroy, VIC 3065, Australia.
Int J Mol Sci. 2021 Sep 5;22(17):9616. doi: 10.3390/ijms22179616.
The AMP-activated protein kinase (AMPK), a central regulator of cellular energy balance and metabolism, binds glycogen via its β subunit. However, the physiological effects of disrupting AMPK-glycogen interactions remain incompletely understood. To chronically disrupt AMPK-glycogen binding, AMPK β double knock-in (DKI) mice were generated with mutations in residues critical for glycogen binding in both the β1 (W100A) and β2 (W98A) subunit isoforms. We examined the effects of this DKI mutation on whole-body substrate utilization, glucose homeostasis, and tissue glycogen dynamics. Body composition, metabolic caging, glucose and insulin tolerance, serum hormone and lipid profiles, and tissue glycogen and protein content were analyzed in chow-fed male DKI and age-matched wild-type (WT) mice. DKI mice displayed increased whole-body fat mass and glucose intolerance associated with reduced fat oxidation relative to WT. DKI mice had reduced liver glycogen content in the fed state concomitant with increased utilization and no repletion of skeletal muscle glycogen in response to fasting and refeeding, respectively, despite similar glycogen-associated protein content relative to WT. DKI liver and skeletal muscle displayed reductions in AMPK protein content versus WT. These findings identify phenotypic effects of the AMPK DKI mutation on whole-body metabolism and tissue AMPK content and glycogen dynamics.
AMP 激活的蛋白激酶（AMPK）是细胞能量平衡和代谢的核心调节剂，通过其β亚基与糖原结合。然而，破坏 AMPK-糖原相互作用的生理影响仍不完全清楚。为了慢性破坏 AMPK-糖原结合，我们生成了 AMPKβ双敲入（DKI）小鼠，其在β1（W100A）和β2（W98A）亚基同工型中对于糖原结合至关重要的残基发生突变。我们研究了这种 DKI 突变对全身底物利用、葡萄糖稳态和组织糖原动力学的影响。在喂食正常饮食的雄性 DKI 和年龄匹配的野生型（WT）小鼠中分析了身体成分、代谢笼、葡萄糖和胰岛素耐量、血清激素和脂质谱以及组织糖原和蛋白质含量。与 WT 相比，DKI 小鼠表现出全身脂肪量增加和葡萄糖不耐受，伴有相对于 WT 的脂肪氧化减少。DKI 小鼠在进食状态下肝脏糖原含量降低，同时在禁食和再喂养时分别增加利用而不补充骨骼肌糖原，尽管相对于 WT，糖原相关蛋白含量相似。DKI 肝和骨骼肌中的 AMPK 蛋白含量相对于 WT 降低。这些发现确定了 AMPK DKI 突变对全身代谢和组织 AMPK 含量以及糖原动力学的表型影响。
