The intrinsically disordered protein TgIST from Toxoplasma gondii inhibits STAT1 signaling by blocking cofactor recruitment

Zhou Huang, Hejun Liu, Jay Nix, Rui Xu, Catherine R. Knoverek, Gregory R. Bowman, Gaya K. Amarasinghe, L. David Sibley

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

Signal transducer and activator of transcription (STAT) proteins communicate from cell-surface receptors to drive transcription of immune response genes. The parasite Toxoplasma gondii blocks STAT1-mediated gene expression by secreting the intrinsically disordered protein TgIST that traffics to the host nucleus, binds phosphorylated STAT1 dimers, and occupies nascent transcription sites that unexpectedly remain silenced. Here we define a core region within internal repeats of TgIST that is necessary and sufficient to block STAT1-mediated gene expression. Cellular, biochemical, mutational, and structural data demonstrate that the repeat region of TgIST adopts a helical conformation upon binding to STAT1 dimers. The binding interface is defined by a groove formed from two loops in the STAT1 SH2 domains that reorient during dimerization. TgIST binding to this newly exposed site at the STAT1 dimer interface alters its conformation and prevents the recruitment of co-transcriptional activators, thus defining the mechanism of blocked transcription.

Original languageEnglish
Article number4047
JournalNature communications
Volume13
Issue number1
DOIs
StatePublished - Dec 2022

Fingerprint

Dive into the research topics of 'The intrinsically disordered protein TgIST from Toxoplasma gondii inhibits STAT1 signaling by blocking cofactor recruitment'. Together they form a unique fingerprint.

Cite this