摘要：骨折不愈合一直是骨科临床的难题，软骨细胞的分化与成熟是骨折愈合的关键。GIT1是骨折愈合过程中重要的调节蛋白，我们已经证实GIT1参与了骨折愈合过程中的细胞分化过程(YIN G et al: 2010，CBI; 2010，JCP; 2012，MCB)。本研究通过GIT1基因敲除小鼠骨折的动物模型，Micro-CT，免疫杂交，免疫共沉淀，免疫组化和荧光素酶报告基因检测等方法探讨GIT1在调节软骨细胞分化的骨形态发生蛋白BMP信号通路中的作用。GIT1通过自身ANK重复区域的二聚体和丝氨酸磷酸化，发挥穿梭蛋白的功能，将BMP/Runx2的信号准确地传递到细胞核内的靶基因，促进软骨细胞的分化和成熟，最终达到骨折愈合。阐明GIT1在软骨细胞分化中的作用，不仅丰富我们对骨折愈合机制的认识，同时也为临床更准确地预防和治疗骨折不愈合提供坚实的理论基础。

Non-union of bone fracture is a serious problem in clinical orthopaedics. Chondrocyte differentiation and maturation are key steps of bone healing. G-protein coupled receptor kinase-interacting protein 1 (GIT1) is an important protein in bone healing processes. We proved that GIT1 play a role in chondrocyte differentiation and maturation in bone healing processes (Yin G et al: 2010, CBI; 2010, JCP; 2012, MCB). We will explore the function of GIT1 on BMP signaling pathway by Micro-CT, immunoblotting, immunoprecipitation, immunofluorescence and luciferase report gene assay in GIT1 wild type (GIT1WT) and GIT1 knock out (GIT1KO) mice. The Ankyrin repeat domain of GIT1 forms dimer, serine phosphorylates and interacts with RunX2, which will transfer to chondrocyte nuclear to promote the differentiation and maturation. To explore the function of GIT1 in chondrocyte differentiation and maturation, not only can understand the mechanism of bone healing processes but also can prevent and treat the non-union of bone fracture.