Renton Mark C, Humphrey Sean J, Connor Tim, Martin Sheree D, Kemerer Krystal, Fernando Hilary, Shaw Christopher S, James David E, Howlett Kirsten F, McGee Sean L
School of Exercise and Nutrition Science, Institute for Physical Activity and Nutrition, Deakin University, Geelong, Victoria, Australia.
Fralin Biomedical Research Institute, Virginia Tech Carilion, Roanoke, Virginia, United States.
Am J Physiol Endocrinol Metab. 2025 Jul 1;329(1):E67-E85. doi: 10.1152/ajpendo.00391.2024. Epub 2025 Jun 2.
The protein kinase D (PKD) family of three highly homologous isoforms (PKD1, PKD2, and PKD3) is implicated as nutrient sensing signaling kinases that regulate the response of adipose and other tissues to the nutrient environment. However, the physiological role of adipose tissue PKD and its downstream cellular signaling targets are not well characterized. Here, we used phosphoproteomics that was performed to elucidate signaling events downstream of PKD activation in differentiated 3T3-L1 adipocytes using a triple isoform siRNA knockdown model. This revealed PKD-regulated pathways including insulin and cAMP signaling, which control metabolic responses in adipose tissue. An adipose tissue-specific and inducible dominant negative PKD (atDNPKD) mouse model that achieves functional inhibition of all three PKD isoforms was generated to assess the function of adipose PKD on whole body metabolism in vivo in both male and female mice. Insulin-stimulated suppression of lipolysis was blunted in male, but not in female, atDNPKD mice compared with control mice. Female, but not male, atDNPKD mice had higher fasting insulin but normal insulin action. Male atDNPKD mice showed greater sensitivity to the β-adrenergic receptor agonist CL316,243 on measures of lipolysis and energy expenditure and displayed greater fat oxidation during fasting. During refeeding, male atDNPKD mice consumed less food and took longer to regain body weight that was lost during fasting. These effects were not observed in female mice. These findings indicate that PKD provides sex-dependent fine-tuning control of cAMP signaling in adipose tissue which is important for the coordination of energy balance during fasting and refeeding. The protein kinase D (PKD) family is a target for the treatment of obesity-related disorders. However, the physiological role of PKD in adipose tissue remains to be resolved. Using phosphoproteomics and an adipose tissue PKD loss-of-function mouse model, results demonstrate that PKD provides fine-tuning of metabolic signaling in adipose tissue and metabolic responses to fasting and refeeding challenges, via coordination of feeding behavior and regulation of body weight.
蛋白激酶D（PKD）家族由三种高度同源的异构体（PKD1、PKD2和PKD3）组成，被认为是营养感应信号激酶，可调节脂肪组织和其他组织对营养环境的反应。然而，脂肪组织PKD及其下游细胞信号靶点的生理作用尚未得到充分表征。在这里，我们使用磷酸化蛋白质组学方法，通过三重异构体siRNA敲低模型，在分化的3T3-L1脂肪细胞中阐明PKD激活下游的信号事件。这揭示了PKD调节的途径，包括胰岛素和cAMP信号传导，它们控制脂肪组织中的代谢反应。我们构建了一种脂肪组织特异性且可诱导的显性负性PKD（atDNPKD）小鼠模型，该模型可实现对所有三种PKD异构体的功能抑制，以评估脂肪组织PKD在雄性和雌性小鼠体内对全身代谢的功能。与对照小鼠相比，胰岛素刺激的脂肪分解抑制在雄性atDNPKD小鼠中减弱，但在雌性小鼠中未减弱。雌性atDNPKD小鼠空腹胰岛素水平较高，但胰岛素作用正常，而雄性小鼠则不然。雄性atDNPKD小鼠在脂肪分解和能量消耗指标上对β-肾上腺素能受体激动剂CL316,243表现出更高的敏感性，并且在禁食期间脂肪氧化增加。在重新进食期间，雄性atDNPKD小鼠进食较少，恢复禁食期间体重减轻所需的时间更长。这些效应在雌性小鼠中未观察到。这些发现表明，PKD对脂肪组织中的cAMP信号传导提供性别依赖性的精细调节控制，这对于禁食和重新进食期间能量平衡的协调很重要。蛋白激酶D（PKD）家族是治疗肥胖相关疾病的一个靶点。然而，PKD在脂肪组织中的生理作用仍有待解决。通过磷酸化蛋白质组学和脂肪组织PKD功能丧失小鼠模型，结果表明PKD通过协调进食行为和调节体重，对脂肪组织中的代谢信号以及对禁食和重新进食挑战的代谢反应进行精细调节。
