Legendre-Guillemin Valerie, Metzler Martina, Lemaire Jean-Francois, Philie Jacynthe, Gan Lu, Hayden Michael R, McPherson Peter S
Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 rue University, Montreal, Quebec H3A 2B4, Canada.
J Biol Chem. 2005 Feb 18;280(7):6101-8. doi: 10.1074/jbc.M408430200. Epub 2004 Nov 8.
Huntingtin interacting protein 1 (HIP1) is a component of clathrin coats. We previously demonstrated that HIP1 promotes clathrin assembly through its central helical domain, which binds directly to clathrin light chains (CLCs). To better understand the relationship between CLC binding and clathrin assembly we sought to dissect this interaction. Using C-terminal deletion constructs of the HIP1 helical domain, we identified a region between residues 450 and 456 that is required for CLC binding. Within this region, point mutations showed the importance of residues Leu-451, Leu-452, and Arg-453. Mutants that fail to bind CLC are unable to promote clathrin assembly in vitro but still mediate HIP1 homodimerization and heterodimerization with the family member HIP12/HIP1R. Moreover, HIP1 binding to CLC is necessary for HIP1 targeting to clathrin-coated pits and clathrin-coated vesicles. Interestingly, HIP1 binds to a highly conserved region of CLC previously demonstrated to regulate clathrin assembly. These results suggest a role for HIP1/CLC interactions in the regulation of clathrin assembly.
亨廷顿相互作用蛋白1（HIP1）是网格蛋白包被的一个组成部分。我们之前证明，HIP1通过其中心螺旋结构域促进网格蛋白组装，该结构域直接与网格蛋白轻链（CLCs）结合。为了更好地理解CLC结合与网格蛋白组装之间的关系，我们试图剖析这种相互作用。利用HIP1螺旋结构域的C端缺失构建体，我们确定了450至456位残基之间的一个区域，该区域是CLC结合所必需的。在这个区域内，点突变显示了Leu-451、Leu-452和Arg-453残基的重要性。无法结合CLC的突变体在体外无法促进网格蛋白组装，但仍能介导HIP1同二聚化以及与家族成员HIP12/HIP1R的异二聚化。此外，HIP1与CLC的结合对于HIP1靶向网格蛋白包被小窝和网格蛋白包被囊泡是必需的。有趣的是，HIP1与CLC的一个高度保守区域结合，该区域先前已被证明可调节网格蛋白组装。这些结果表明HIP1/CLC相互作用在调节网格蛋白组装中发挥作用。
