Activation of atypical protein kinase Czeta toward TC10 is regulated by high-fat diet and aerobic exercise in skeletal muscle
Saito, M., Lessard, S. J, Rivas, D. A, Reeder, D. W, Hawley, J. A & Yaspelkis, BB. (2008). Activation of atypical protein kinase Czeta toward TC10 is regulated by high-fat diet and aerobic exercise in skeletal muscle. Metabolism: Clinical and experimental,57(9), 1173-1180. The Netherlands: Elsevier. Retrieved from https://doi.org/10.1016/j.metabol.2008.03.023
We determined whether sustained aerobic exercise reverses high-fat diet–induced impairments in the c-Cbl associated protein (CAP)/Casitas b-lineage lymphoma (c-Cbl) signaling cascade in rodent skeletal muscle. Sprague-Dawley rats were placed into either control (n = 16) or high-fat–fed (n = 32) diet groups for 4 weeks. During a subsequent 4-week experimental period, 16 high-fat–fed rats remained sedentary, 16 high-fat–fed rats completed 4 weeks of exercise training, and control animals were sedentary and remained on the control diet. After the intervention period, animals were subjected to hind limb perfusions in the presence (n = 8 per group) or absence (n = 8 per group) of insulin. In the plasma membrane fractions, neither high-fat feeding nor exercise training altered adaptor protein with PH and SH2 domains, (APS), c-Cbl, or TC10 protein concentrations. In contrast, CAP protein concentration and insulin-stimulated plasma membrane c-Cbl tyrosine phosphorylation were reduced by high-fat feeding; but exercise training reversed these impairments. Of note was that insulin-stimulated atypical protein kinase Cζ kinase activity toward TC10 was reduced by high-fat feeding but normalized by exercise training. We conclude that sustained (4 weeks) exercise training can reverse high-fat diet–induced impairments on the CAP/c-Cbl pathway in high-fat–fed rodent skeletal muscle. We also provide the first evidence that the CAP/c-Cbl insulin signaling cascade in skeletal muscle may directly interact with components of the classic (phosphoinositide 3-kinase dependent) insulin signaling cascade.