School of Neuroscience, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA.
Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA.
Neuroscience. 2019 Oct 15;418:1-14. doi: 10.1016/j.neuroscience.2019.08.031. Epub 2019 Aug 23.
The ubiquitin-proteasome system (UPS) controls the degradation of ~90% of short-lived proteins in cells and is involved in activity- and learning-dependent synaptic plasticity in the brain. Calcium/calmodulin dependent protein kinase II (CaMKII) and Protein Kinase A (PKA) can regulate activity of the proteasome. However, there have been a number of conflicting reports regarding under what conditions CaMKII and PKA regulate proteasome activity in the brain. Furthermore, this work has been done exclusively in males, leaving questions about whether these kinases also regulate the proteasome in females. Here, using subcellular fractionation protocols in combination with in vitro pharmacology and proteasome activity assays, we investigated the conditions under which CaMKII and PKA regulate proteasome activity in the brains of male and female rats. In males, nuclear proteasome chymotrypsin activity was regulated by PKA in the amygdala but CaMKII in the hippocampus. Conversely, in females CaMKII regulated nuclear chymotrypsin activity in the amygdala, but not hippocampus. Additionally, in males CaMKII and PKA regulated proteasome trypsin activity in the cytoplasm of hippocampal, but not amygdala cells, while in females both CaMKII and PKA could regulate this activity in the nucleus of cells in both regions. Proteasome peptidylglutamyl activity was regulated by CaMKII and PKA activity in the nuclei of amygdala and hippocampus cells in males. However, in females PKA regulated nuclear peptidylglutamyl activity in the amygdala, but not hippocampus. Collectively, these results suggest that CaMKII- and PKA-dependent regulation of proteasome activity in the brain varies significantly across subcellular compartments and between males and females.
泛素-蛋白酶体系统（UPS）控制着细胞中约 90%的短寿命蛋白的降解，并且参与大脑中与活动和学习相关的突触可塑性。钙/钙调蛋白依赖性蛋白激酶 II（CaMKII）和蛋白激酶 A（PKA）可以调节蛋白酶体的活性。然而，关于 CaMKII 和 PKA 在何种条件下调节大脑中的蛋白酶体活性，已经有许多相互矛盾的报道。此外，这项工作仅在雄性中进行，这使得人们对于这些激酶是否也调节雌性中的蛋白酶体产生了疑问。在这里，我们使用亚细胞分级分离方案结合体外药理学和蛋白酶体活性测定，研究了 CaMKII 和 PKA 调节雄性和雌性大鼠大脑中蛋白酶体活性的条件。在雄性中，PKA 在杏仁核中调节核蛋白酶体糜蛋白酶活性，而 CaMKII 在海马体中调节核蛋白酶体糜蛋白酶活性。相反，在雌性中，CaMKII 调节杏仁核中的核糜蛋白酶活性，但不调节海马体中的核糜蛋白酶活性。此外，在雄性中，CaMKII 和 PKA 调节海马体细胞质中的蛋白酶体胰蛋白酶活性，但不调节杏仁核细胞中的胰蛋白酶活性，而在雌性中，CaMKII 和 PKA 都可以调节这两个区域中细胞的核蛋白酶体胰蛋白酶活性。在雄性中，CaMKII 和 PKA 调节杏仁核和海马体细胞核中的蛋白酶体肽基谷氨酰活性。然而，在雌性中，PKA 调节杏仁核中的核肽基谷氨酰活性，但不调节海马体中的核肽基谷氨酰活性。总的来说，这些结果表明，CaMKII 和 PKA 依赖性调节蛋白酶体活性在大脑中的不同亚细胞隔室和雄性和雌性之间存在显著差异。
