University of Science and Technology of China, Hefei, Anhui 230026, China.
Proc Natl Acad Sci U S A. 2011 Jul 26;108(30):12277-82. doi: 10.1073/pnas.1013101108. Epub 2011 Jul 11.
SNARE proteins are crucial for membrane fusion in vesicular transport. To ensure efficient and accurate fusion, SNAREs need to be sorted into different budding vesicles. This process is usually regulated by specific recognition between SNAREs and their adaptor proteins. How different pairs of SNAREs and adaptors achieve their recognition is unclear. Here, we report the recognition between yeast SNARE Vti1p and its adaptor Ent3p derived from three crystal structures. Surprisingly, this yeast pair Vti1p/Ent3p interacts through a distinct binding site compared to their homologues vti1b/epsinR in mammals. An opposite surface on Vti1p_Habc domain binds to a conserved area on the epsin N-terminal homology (ENTH) domain of Ent3p. Two-hybrid, in vitro pull-down and in vivo experiments indicate this binding interface is important for correct localization of Vti1p in the cell. This previously undescribed discovery that a cargo and adaptor pair uses different binding sites across species suggests the diversity of SNARE-adaptor recognition in vesicular transport.
SNARE 蛋白对于囊泡运输中的膜融合至关重要。为了确保高效和准确的融合，SNARE 必须被分类到不同的出芽小泡中。这个过程通常受到 SNARE 与其衔接蛋白之间特异性识别的调节。不同的 SNARE 对和衔接蛋白如何实现它们的识别尚不清楚。在这里，我们报道了来自三个晶体结构的酵母 SNARE Vti1p 与其衔接蛋白 Ent3p 之间的识别。令人惊讶的是，与哺乳动物中的同源物 vti1b/epsinR 相比，酵母对 Vti1p/Ent3p 通过一个独特的结合位点相互作用。Vti1p_Habc 结构域的相反表面与 Ent3p 的 epsin N 端同源 (ENTH) 结构域上的保守区域结合。双杂交、体外下拉和体内实验表明，这个结合界面对于 Vti1p 在细胞中的正确定位是重要的。这一先前未被描述的发现，即货物和衔接蛋白对在不同物种中使用不同的结合位点，表明囊泡运输中 SNARE-衔接蛋白识别的多样性。
