Regulatory interaction of phosducin-like protein with the cytosolic chaperonin complex

Joseph N. McLaughlin, Craig D. Thulin, Sarah J. Hart, Katheryn A. Resing, Natalie G. Ahn, Barry M. Willardson

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Abstract

Phosducin and phosducin-like protein (PhLP) bind G protein βγ subunits and regulate their activity. This report describes a previously uncharacterized binding partner unique to PhLP that was discovered by coimmunoprecipitation coupled with mass spectrometric identification. Chaperonin containing tailless complex polypeptide 1 (CCT), a cytosolic chaperone responsible for the folding of many cellular proteins, binds PhLP with a stoichiometry of one PhLP per CCT complex. Unlike protein-folding substrates of CCT, which interact only in their nonnative conformations, PhLP binds in its native state. Native PhLP competes directly for binding of protein substrates of CCT and thereby inhibits CCT activity. Overexpression of PhLP inhibited the ability of CCT to fold newly synthesized β-actin by 80%. These results suggest that the interaction between PhLP and CCT may be a means to regulate CCT-dependent protein folding or alternatively, to control the availability of PhLP to modulate G protein signaling.

Original languageEnglish (US)
Pages (from-to)7962-7967
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume99
Issue number12
DOIs
StatePublished - Jun 11 2002

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