Discovery of an exosite on the SOCS2-SH2 domain that enhances SH2 binding to phosphorylated ligands

Edmond M Linossi; Kunlun Li; Gianluca Veggiani; Cyrus Tan; Farhad Dehkhoda; Colin Hockings; Dale J Calleja; Narelle Keating; Rebecca Feltham; Andrew J Brooks; Shawn S Li; Sachdev S Sidhu; Jeffrey J Babon; Nadia J Kershaw; Sandra E Nicholson

doi:10.1038/s41467-021-26983-5

Discovery of an exosite on the SOCS2-SH2 domain that enhances SH2 binding to phosphorylated ligands

Nat Commun. 2021 Dec 2;12(1):7032. doi: 10.1038/s41467-021-26983-5.

Authors

Edmond M Linossi^#^{1

2}, Kunlun Li^#^{1

2}, Gianluca Veggiani^#³, Cyrus Tan^{1

2}, Farhad Dehkhoda^{1

2}, Colin Hockings^{1

2}, Dale J Calleja^{1

2}, Narelle Keating^{1

2}, Rebecca Feltham^{1

2}, Andrew J Brooks⁴, Shawn S Li⁵, Sachdev S Sidhu³, Jeffrey J Babon^{1

2}, Nadia J Kershaw^{6

7}, Sandra E Nicholson^{8

9}

Affiliations

¹ The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia.
² Department of Medical Biology, University of Melbourne, Parkville, VIC, Australia.
³ The Donnelly Center for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, Canada.
⁴ The University of Queensland Diamantina Institute, Woolloongabba, QLD, 4102, Australia.
⁵ Department of Biochemistry and the Siebens-Drake Medical Research Institute, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada.
⁶ The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia. kershaw@wehi.edu.au.
⁷ Department of Medical Biology, University of Melbourne, Parkville, VIC, Australia. kershaw@wehi.edu.au.
⁸ The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia. snicholson@wehi.edu.au.
⁹ Department of Medical Biology, University of Melbourne, Parkville, VIC, Australia. snicholson@wehi.edu.au.

^# Contributed equally.

Abstract

Suppressor of cytokine signaling (SOCS)2 protein is a key negative regulator of the growth hormone (GH) and Janus kinase (JAK)-Signal Transducers and Activators of Transcription (STAT) signaling cascade. The central SOCS2-Src homology 2 (SH2) domain is characteristic of the SOCS family proteins and is an important module that facilitates recognition of targets bearing phosphorylated tyrosine (pTyr) residues. Here we identify an exosite on the SOCS2-SH2 domain which, when bound to a non-phosphorylated peptide (F3), enhances SH2 affinity for canonical phosphorylated ligands. Solution of the SOCS2/F3 crystal structure reveals F3 as an α-helix which binds on the opposite side of the SH2 domain to the phosphopeptide binding site. F3:exosite binding appears to stabilise the SOCS2-SH2 domain, resulting in slower dissociation of phosphorylated ligands and consequently, enhances binding affinity. This biophysical enhancement of SH2:pTyr binding affinity translates to increase SOCS2 inhibition of GH signaling.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

A549 Cells
Amino Acid Sequence
Binding Sites
Cloning, Molecular
Crystallography, X-Ray
Escherichia coli / genetics
Escherichia coli / metabolism
Gene Expression
Genetic Vectors / chemistry
Genetic Vectors / metabolism
HEK293 Cells
Humans
Models, Molecular
Phosphorylation
Protein Binding
Protein Conformation, alpha-Helical
Protein Conformation, beta-Strand
Protein Interaction Domains and Motifs
Recombinant Proteins / chemistry
Recombinant Proteins / genetics
Recombinant Proteins / metabolism
Sequence Alignment
Sequence Homology, Amino Acid
Suppressor of Cytokine Signaling Proteins / chemistry*
Suppressor of Cytokine Signaling Proteins / genetics
Suppressor of Cytokine Signaling Proteins / metabolism
Tyrosine / chemistry*
Tyrosine / metabolism

Substances

Recombinant Proteins
SOCS2 protein, human
Suppressor of Cytokine Signaling Proteins
Tyrosine