骨折不愈合一直是骨科临床的难题，目前的研究普遍认为：骨折端的新生血管形成是骨折如期愈合的关键。GIT1是骨折愈合过程中的重要蛋白质，我们已经证实GIT1参与骨折愈合过程中的新生血管形成(Yin G et al: 2010 CBI；2012 MCB；2014 PLoS One)。HIF-1α是调节新生血管形成的关键蛋白质，GIT1具有稳定HIF-1α的作用(Yin G et al: 2012 IJMM),但机制不详。本研究采用国内唯一具有的GIT1基因敲除型小鼠，建立经典骨折模型，探讨GIT1在调节HIF-1α信号通路中的作用。GIT1通过SHD结构域内成簇的带阳性电荷的KKRRKKK氨基酸基团，与pVHL竞争HIF-1α中带阴性电荷的羟基（Pro402和Pro564），稳定HIF-1α的表达，促进骨折端新生血管形成。此研究丰富对骨折愈合机制的认识，为临床治疗骨折不愈合提供坚实的理论依据。

Non-union of bone fracture is a serious problem in clinical orthopaedics. The angiogenesis is key step for 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 angiogenesis in bone healing processes (Yin G et al: 2010, CBI; 2012, MCB；2014, PLoS One). We will explore the function of GIT1 on HIF-αsignaling pathway by Micro-CT, immunoblotting, immunoprecipitation, immunofluorescence and luciferase report gene assay in GIT1 wild type (GIT1WT) and GIT1 knock out (GIT1KO) mice. The cluster and positive charge amino acid in SHD domain of GIT1 interact with proline 402 and proline 564 in HIF-α? by competing with pVHL. It will enhance the HIF-α? stability and nuclear transcription to promote the angiogenesis and bone healing. To explore the function of GIT1 in angiogenesis, not only can understand the mechanism of bone healing processes but also can prevent and treat the non-union of bone fracture.