School of Biochemistry and Immunology, Trinity College Dublin, 152-160 Pearse Street, Dublin D2, Ireland.
Acta Crystallogr F Struct Biol Commun. 2020 Aug 1;76(Pt 8):357-363. doi: 10.1107/S2053230X20009164. Epub 2020 Jul 28.
The small GTPases Rab11, Rab14 and Rab25 regulate membrane trafficking through the recruitment of Rab11 family-interacting proteins (FIPs) to endocytic compartments. FIPs are multi-domain effector proteins that have a highly conserved Rab-binding domain (RBD) at their C-termini. Several structures of complexes of Rab11 with RBDs have previously been determined, including those of Rab11-FIP2 and Rab11-FIP3. In addition, the structures of the Rab14-FIP1 and Rab25-FIP2 complexes have been determined. All of the RBD structures contain a central parallel coiled coil in the RBD that binds to the switch 1 and switch 2 regions of the Rab. Here, the crystal structure of the uncomplexed RBD of FIP2 is presented at 2.3 Å resolution. The structure reveals antiparallel α-helices that associate through polar interactions. These include a remarkable stack of arginine residues within a four-helix bundle in the crystal lattice.
小分子 GTP 酶 Rab11、Rab14 和 Rab25 通过招募 Rab11 家族相互作用蛋白（FIP）到内吞小体来调节膜运输。FIP 是多结构域效应蛋白，其 C 末端具有高度保守的 Rab 结合结构域（RBD）。之前已经确定了 Rab11 与 RBD 形成的复合物的几个结构，包括 Rab11-FIP2 和 Rab11-FIP3。此外，还确定了 Rab14-FIP1 和 Rab25-FIP2 复合物的结构。所有 RBD 结构都包含 RBD 中的中央平行卷曲螺旋，该螺旋与 Rab 的开关 1 和开关 2 区域结合。在此，呈现了 2.3 Å 分辨率的 FIP2 未结合 RBD 的晶体结构。该结构揭示了通过极性相互作用关联的反平行 α-螺旋。其中包括在晶格中的四螺旋束内的精氨酸残基的显著堆积。
