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Updated: May 20, 2026

In vivo and in vitro Studies of Adaptor-clathrin Interaction
17:14

In vivo and in vitro Studies of Adaptor-clathrin Interaction

Published on: January 26, 2011

Two Distantly Spaced Basic Patches in the Flexible Domain of Huntingtin-Interacting Protein 1 (HIP1) Are Essential

Joel A Ybe1, Mary E Clegg, Melissa Illingworth

  • 1Department of Biology, Indiana University, Simon Hall 405B, 212 S. Hawthorne Drive, Bloomington, IN 47405, USA.

Research Letters in Biochemistry
|July 24, 2012
PubMed

Insights

HIP1 and HIP12/1R proteins are crucial for endocytosis. Researchers used circular dichroism to find that specific mutations in HIP1 affect its binding to clathrin light chain, suggesting varied binding mechanisms across species.

Area of Science:

  • Cell Biology
  • Biochemistry
  • Structural Biology

Background:

  • The interaction between HIP family proteins (HIP1 and HIP12/1R) and clathrin is fundamental to the process of endocytosis.
  • Understanding these protein interactions is key to elucidating cellular trafficking mechanisms.

Purpose of the Study:

  • To investigate the structural stability of an HIP1 subfragment (aa468-530) using circular dichroism (CD).
  • To identify the binding site of clathrin light chain on HIP1 and determine the role of specific residues in this interaction.
  • To compare the conservation of these binding sites across different species.

Main Methods:

  • Circular dichroism (CD) thermal melts were employed to assess the stability of the HIP1 468-530 subfragment.
  • Site-directed mutagenesis was used to create HIP1 mutants to probe the clathrin light chain binding site.
  • Comparative analysis of residue conservation in HIP1 homologs from various organisms.

Main Results:

  • The HIP1 468-530 subfragment exhibited limited stability at higher temperatures but contained a stable structural unit.
  • The binding of clathrin light chain (hub/LCb) to HIP1 was sensitive to mutations at basic residues K474 and K494.
  • These identified basic patches are conserved in HIP12/1R but not in homologs from yeast, fruit fly, or C. elegans.

Conclusions:

  • A specific structural region within HIP1 is involved in clathrin light chain binding.
  • The identified basic residues K474 and K494 play a critical role in mediating this interaction.
  • The differential conservation of these binding sites suggests that HIP1 and its homologs may interact with clathrin light chain through distinct mechanisms in different organisms.

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