Chen Fanghui, Xiang Minghui, Wang Zhipeng, Yang Fan, Zhou Junzhi, Deng Zihan, Wang Susu, Li Ping, Tew Jieqi, Zhang Wei, Li Honglin, Teng Yong, Zhu Xiaobin, Cai Yafei
College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China.
Department of Human Anatomy, Bengbu Medical College, Bengbu, 233030, China.
Cell Death Discov. 2025 Apr 6;11(1):146. doi: 10.1038/s41420-025-02414-y.
CDK5RAP3 is a binding protein of CDK5 activating proteins and also one of the key co-factors of the E3 enzyme in the UFMylation system. Several reports have implicated the involvement of CDK5 and other components of the UFMylation system in neuronal development and multiple psychiatric disorders. However, the precise role of CDK5RAP3 in neurons remains elusive. In this study, we generated CDK5RAP3 neuron-specific knockout mice (CDK5RAP: Nestin-Cre). CDK5RAP3 conditional knockout (CDK5RAP3 CKO) mice exhibited severe encephalo-dysplasia and a slower developmental trajectory compared to wild-type (WT) mice and succumbed to postnatal demise by day 14. Transcriptome sequencing unveiled that CDK5RAP3 deficiency affects synapse formation, transmembrane trafficking and physiological programs in the brain. Morphological analysis demonstrated that neuronal CDK5RAP3 deficiency leads to increased SLC17A6 and N-glycosylase (RPN1 and ALG2) protein expression, and while causing endoplasmic reticulum (ER) stress. In vitro experiments utilizing CDK5RAP3: ROSA26-ERT2Cre MEFs were conducted to elucidate similar mechanism following CDK5RAP3 deletion. Both in vivo and in vitro, CDK5RAP3 deficiency significantly increased the expression of N-glycosylases (RPN1 and ALG2), as well as the total amount of glycoproteins. CDK5RAP3 may potentially maintain a balance by enhancing the degradation of RPN1 and ALG2 through proteolytic degradation pathways and autophagy. This study underscores the indispensable role of CDK5RAP3 in neuronal development and sheds new light on drug discovery endeavors targeting early brain abnormalities.
CDK5RAP3是CDK5激活蛋白的结合蛋白，也是泛素样修饰系统中E3酶的关键辅助因子之一。多项报告表明，CDK5及泛素样修饰系统的其他成分参与神经元发育和多种精神疾病。然而，CDK5RAP3在神经元中的具体作用仍不清楚。在本研究中，我们构建了CDK5RAP3神经元特异性敲除小鼠（CDK5RAP：Nestin-Cre）。与野生型（WT）小鼠相比，CDK5RAP3条件性敲除（CDK5RAP3 CKO）小鼠表现出严重的脑发育异常和发育轨迹迟缓，并在出生后第14天死亡。转录组测序显示，CDK5RAP3缺陷影响大脑中的突触形成、跨膜运输和生理程序。形态学分析表明，神经元CDK5RAP3缺陷导致SLC17A6和N-糖基化酶（RPN1和ALG2）蛋白表达增加，并引起内质网（ER）应激。利用CDK5RAP3：ROSA26-ERT2Cre MEFs进行体外实验，以阐明CDK5RAP3缺失后的类似机制。在体内和体外，CDK5RAP3缺陷均显著增加N-糖基化酶（RPN1和ALG2）的表达以及糖蛋白的总量。CDK5RAP3可能通过蛋白水解降解途径和自噬增强RPN1和ALG2的降解来维持平衡。本研究强调了CDK5RAP3在神经元发育中的不可或缺作用，并为针对早期脑异常的药物发现努力提供了新的线索。
