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Arrestin binding to microtubules involves a distinct conformational change
Author(s) -
Hanson Susan M,
Francis Derek J,
Vishnivetskiy Sergey A,
Raman Dayanidhi,
Van Eps Ned,
Hubbell Wayne L,
Klug Candice S,
Gurevich Vsevolod V
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a110-a
Subject(s) - microtubule , conformational change , biophysics , chemistry , microbiology and biotechnology , biology
Arrestins play a key role in the regulation of signaling by G protein‐coupled receptors. We found that all four mammalian arrestins directly bind microtubules (MTs) with Kds of 25–50 uM. In the case of rod arrestin which self‐associates into tetramers in solution, both monomer and tetramer bind MTs. Using site‐directed mutagenesis and spin labeling/EPR we identified the concave side of the two arrestin domains as the MT‐binding surface in rod arrestin and arrestin2. This site significantly overlaps with the receptor‐binding site, making arrestin interactions with receptors and MTs mutually exclusive. Similar to the receptor, MT binding induces the release of the arrestin C‐tail. The deletion of the C‐tail and other mutations destabilizing the basal conformation of arrestin enhance binding to MTs, suggesting that arrestins undergo a conformational change in the process. Deletions in the inter‐domain hinge that hinder receptor binding enhance the arrestin‐MT interaction, suggesting that the receptor‐ and MT‐bound arrestin conformations are different. The extent of the co‐localization of wild type and mutant arrestins with MTs in cells and their co‐purification with the cytoskeletal fraction is proportional to their affinity for MTs determined in vitro. Thus, arrestins in living cells exist in at least three distinct conformations: basal (free), receptor‐bound, and MT‐bound. Funded by NIH grants EY11500, GM63097, AI58024, GM70642, EY05216.