稻米中蛋白质的含量和组成对其品质形成起着重要的作用，因此，解析种子蛋白合成、分选、积累的分子机制对于稻米的蛋白品质改良至关重要。前期研究中我们利用一系列的谷蛋白57H突变体克隆鉴定了多个蛋白分选关键因子。最近我们从滇粳优1号诱变株系中获得一全新的57H突变体gpa11，切片研究发现gpa11发育胚乳细胞中内质网形态存在缺陷：层状ER（sheet-like ER）减少，ER囊腔膨大及蛋白质在ER中滞留，表明gpa11中存在明显的ER塑型（ER shaping）缺陷，并影响了蛋白的ER输出。GPA11编码一个保守的功能未知的ER定位蛋白。后续将采用各种方法阐明GPA11调控ER shaping分子机制。真核生物中ER-shaping的机制并不十分清楚，目前仅有少数几个调控因子的功能研究报道，本研究将鉴定一个全新的参与ER shaping的关键因子，提高人们对真核生物ER shaping的认知。

The content and composition of rice proteins play important roles in rice quality. Therefore, dissection of the molecular mechanisms underlying biosynthesis, sorting, and accumulation of seed storage proteins are vital to the improvement of rice quality. Our previous studies identified several key factors involved in glutelin trafficking with serials of 57H mutants. In this study, a novel 57H mutant name gpa11 (glutelin precursor accumulation 11) was obtained from the MNU-treated Diangengyou1 mutant lines. Preliminary transmission electron microscopic analysis showed the ER defects in gpa11 developing endosperm, including the decreased sheet-like ER, the dilated ER lumens, and the retention of storage proteins in the ER lumen. Map-based cloning and subsequent complementation analyses revealed that GPA11 encodes a conserved hypothetical protein with unknown function. This protein is localized to the ER. Further study will try to elucidate the molecular mechanisms underlying GPA11 regulated ER shaping and protein exit of the ER. ER shaping in eukaryotes are largely unknown with only a few factors being characterized. Our study will identify a key factor involved in ER shaping, which will provide novel insight for the understanding of ER shaping in eukaryotes.