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Structures of Gα Proteins in Complex with Their Chaperone Reveal Quality Control Mechanisms by Alpay Burak Seven; Daniel Hilger; Makaía M. Papasergi-Scott; Li Zhang; Qianhui Qu; Brian K. Kobilka; Gregory G. Tall; Georgios Skiniotis is a Biochemistry, Genetics and Molecular Biology article available to read on EtoBox.

What is Structures of Gα Proteins in Complex with Their Chaperone Reveal Quality Control Mechanisms about?

## SUMMARY Many chaperones promote nascent polypeptide folding followed by substrate release through ATP-dependent conformational changes. Here we show cryoEM structures of Gα subunit folding intermediates in complex with full-length Ric-8A, a unique chaperone-client system in which substrate release is facilitated by guanine nucleotide binding to the client G protein. The structures of Ric-8A-Gα~i~ and Ric-8A-Gα~q~ complexes reveal that the chaperone employs its extended C-terminal region to cradle the Ras-like domain of Gα, positioning the Ras core in contact with the Ric-8A core while engaging its switch2 nucleotide binding region. The C-terminal α5 helix of Gα is held away from the Ras-like domain through Ric-8A core domain interactions, which critically depend on recognition of the Gα C terminus by the chaperone. The structures, complemented with biochemical and cellular chaperoning data, support a folding quality control mechanism that ensures proper formation of the C-terminal α5 helix before allowing GTP-gated release of Gα from Ric-8A.

Who reads Structures of Gα Proteins in Complex with Their Chaperone Reveal Quality Control Mechanisms?

Author

Alpay Burak Seven; Daniel Hilger; Makaía M. Papasergi-Scott; Li Zhang; Qianhui Qu; Brian K. Kobilka; Gregory G. Tall; Georgios Skiniotis

Published

2020

Language

EN

Field

Biochemistry, Genetics and Molecular Biology (Life Sciences)