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Conformational Changes in β‐arrestin1: The Importance of β‐arrestin1’s N‐domain
Author(s) -
Nobles Kelly Nicole,
Guan Ziqiang,
Xiao Kunhong,
Oas Terrence G.,
Lefkowitz Robert J.
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.a114-a
Subject(s) - phosphopeptide , chemistry , conformational change , proteolysis , internalization , biophysics , transmembrane domain , receptor , microbiology and biotechnology , g protein coupled receptor , peptide , biochemistry , biology , enzyme
β‐arrestins are multifunctional adaptor proteins that regulate seven transmembrane spanning receptor (7TMR) desensitization, internalization and have been shown to initiate alternate signaling pathways. Studies have shown that arrestins undergo a conformational change upon binding activated, phosphorylated 7TMRs. Accordingly, we have determined conformational changes in β‐arrestin1 using limited tryptic proteolysis and MALDI‐TOF MS in the presence of a phosphopeptide from the the human V 2 vasopressin receptor (V 2 Rpp) or an unphosphorylated peptide (V 2 Rnp). V 2 Rpp binds specifically to β‐arrestin1 causing significant conformational changes whereas V 2 Rnp does not alter the conformation. Activation of β‐arrestin1 is demonstrated by the release of its C‐terminus and disruption of its polar core, indicated by increased accessibility of R 393 and R 285 , respectively. We further demonstrate a functional consequence of β‐arrestin1 activation by enhanced clathrin binding. A striking difference in the conformational changes observed in β‐arrestin1 when compared to β‐arrestin2 is the marked protection of the N‐domain. The data are consistent with previous models for arrestin activation and support the idea that the N‐domain is responsible for recognizing phosphates in 7TMRs. This study represents the first direct evidence that the “receptor‐bound” conformations of β‐arrestins1 and 2 are different.