听觉是动物感知外部世界的重要手段。在听觉传导过程中，听觉受体细胞-毛细胞发挥了至关重要的作用。毛细胞的发育及维持受到严格调控，毛细胞发育异常会导致感音神经性聋。我们的前期工作表明蛋白激酶CDK5（cyclin-dependent kinase 5）在内耳毛细胞中表达，在小鼠内耳中特异性敲除CDK5导致毛细胞死亡并引起严重耳聋。据此我们提出CDK5在毛细胞发育和/或维持过程中发挥重要功能。为深入研究CDK5在听觉中的功能并明确相关机制，我们将详细分析CDK5基因敲除小鼠的听力水平以及毛细胞发育、结构和功能，并利用蛋白质组学手段鉴定在毛细胞中表达的CDK5磷酸化靶蛋白。我们的前期工作还表明在已知的CDK5激活因子中只有CCNI（cyclin I）在小鼠成熟毛细胞中高表达，因此我们还将对CCNI基因敲除小鼠的听力水平以及毛细胞发育、结构和功能进行详细分析。

Auditory system provides very important external information for animals. Auditory receptor cells, namely hair cells, play a pivotal role in hearing transduction process. Hair cell development and maintenance are tightly regulated, whereas abnormality of hair cell development results in sensory hearing loss. Our previous work revealed that CDK5 (cyclin-dependent kinase 5) is expressed in hair cells, and disruption of CDK5 in hair cells causes hair cell loss as well as deafness. Hence we propose that CDK5 plays an important role in hair cell development and/or maintenance. In order to further explore the role of CDK5 in hearing, we will analyze the hearing ability as well as hair cell development, structure and function of CDK5 knockout mice. We will identify novel CDK5 target proteins in the mouse inner ear using proteomic tools. Our previous work also revealed that CCNI（cyclin I） is the only CDK5 activator that is highly expressed in mature mouse hair cells, hence we will also analyze the hearing ability as well as hair cell development, structure and function of CCNI knockout mice.