Huntingtin Interacting Protein 1 (HIP1) Regulates Clathrin Assembly through Direct Binding to the Regulatory Region of the Clathrin Light Chain*
- Valerie Legendre-Guillemin‡§,
- Martina Metzler¶,
- Jean-Francois Lemaire‡,
- Jacynthe Philie‡,
- Lu Gan¶,
- Michael R. Hayden¶∥ and
- Peter S. McPherson, Canadian Institutes of Health Research Investigator, a Killam Scholar, and a McGill University William Dawson Scholar‡,**
- ‡Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 2B4, Canada and the ¶Centre for Molecular Medicine and Therapeutics, Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada
- ↵** To whom correspondence should be addressed: Dept. of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 rue University, Montreal, Quebec H3A 2B4, Canada. Tel.: 514-398-7355; Fax: 514-398-8106; E-mail: peter.mcpherson{at}mcgill.ca.
Abstract
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.
- Received July 26, 2004.
- Revision received October 7, 2004.
- The American Society for Biochemistry and Molecular Biology, Inc.
