蛋白质是稻米中主要的营养物质之一，其含量和组成对稻米的品质有着重要的影响。前期研究中我们通过对水稻谷蛋白前体增加突变体gpa1的鉴定发现GPA1/OsRab5a对稻米中最主要的储藏蛋白--谷蛋白的后高尔基体运输是必须的。后续研究中我们通过酵母双杂交实验筛选获得了Rab5a Q70L互作蛋白RIP1，并采用CRIPSR/Cas9技术对RIP1进行了敲除，获得了RIP1的缺失突变体，该突变体表现为谷蛋白前体大量增加，同时胚乳粉质，表型与GPA1十分相似，说明RIP1在谷蛋白的转运中起着重要的作用。另一方面RIP1是一个包含PH结构域的蛋白，该类蛋白功能较为多样，动物和酵母中对其功能解析尚不深入，植物中的研究报道更少，因此，RIP1的功能解析将有助于人们该对该类蛋白功能的认识，同时进一步提高我们对水稻谷蛋白转运途径的理解，为稻米蛋白品质改良奠定基础。

Protein is one of the major nutritional components in rice. The content and composition of protein significantly affects the rice quality. Previous study with the rice 57H mutant gpa1 showed that GPA1/OsRab5a is essential for the post-Golgi trafficking of the major storage protein — glutelin. In our later study, we identified one interacting protein of OsRab5a Q70L (a GTP-locked constitutive active form of OsRab5a) RIP1 (OsRab5a interacting protein 1) through yeast two hybrid assay. Further, we successfully obtained the knockout mutant of RIP1 by CRISPR/Cas9 technique. The rip1 mutant shows the 57H phenotype and floury endosperm, which resembles the phenotype of gpa1, indicating that RIP1 plays important roles in glutelin trafficking as well. In addition, RIP1 contains a pleckstrin homology (PH) domain, which is the 11th most abundant domain class in the human genome and shows diverse functions, such as cellular signaling, cytoskeleton organization, membrane trafficking and/or phospholipid modification. However, the detailed functions of PH domain containing proteins are largely unknown in mammalian cells and yeast, not to mention studies in plants. Therefore, dissection of the molecular function of RIP1 in rice will contribute to the understanding of PH-domain containing proteins. Moreover, increaseing our knowledge on the rice glutelin trafficking pathway, which lays the foundation for protein quality improvement in rice.