Biology subjects

Strutzenberg, T. S.

Publications and source records attributed to Strutzenberg, T. S..

4 recordsLinked to original sources

bioRxiv2025

Nucleosome Engagement Regulates RORγt Structure and Dynamics

ROR{gamma}t is a key transcriptional regulator that supports protective pathogen clearance but also drives autoimmune disorders. Genetic studies have identified ROR{gamma}t mutations that selectively protect from autoimmunity without compromising host defense. Herein, we describe the molecular principles governing how ROR{gamma}t selectively drives these context-dependent gene programs. Structural studies revealed the selectivity-determining mutations lie in an -helix, the C-terminal extension (CTE), which nucleates when ROR{gamma}t engages partially occluded DNA response elements at nucleosome entry/exit sites. In ex vivo Th17 cells, the CTE is required for full genomic occupancy and expression of inflammatory effector genes, while residual DNA binding supports partial occupancy that, alongside context-dependent transcription factors, induces lineage-stabilizing gene expression. These findings support a model where ROR{gamma}t uses distinct chromatin binding modes to engage an expansive chromatin landscape to activate target gene programs, explaining the complex phenotypes of CTE mutant mice.

biophysics↗

bioRxiv2022

Structural basis of interdomain communication in PPARγ

The nuclear receptor peroxisome proliferator-activated receptor gamma (PPAR{gamma}) regulates transcription via two activation function (AF) regulatory domains: a ligand-dependent AF-2 coregulator interaction surface within the C-terminal ligand-binding domain (LBD), and an N-terminal disordered AF-1 domain (NTD or A/B region) that functions through poorly understood structural mechanisms. Here, we show the PPAR{gamma} AF-1 contains an evolutionary conserved Trp-Pro motif that undergoes cis/trans isomerization, populating two long-lived conformations that participate in intradomain AF-1 and interdomain interactions including two surfaces in the C-terminal LBD ({beta}-sheet and the AF-2 surface), which are predicted in AlphaFold 3 models but not AlphaFold 2. NMR and chemical crosslinking mass spectrometry show that interdomain interactions occur for soluble isolated AF-1 and LBD proteins, as well as in full-length PPAR{gamma} in a phase separated state. Mutation of the region containing the Trp-Pro motif, which abrogates cis/trans isomerization of this region, impacts LBD interaction and reduces basal PPAR{gamma}-mediated transcription and agonist-dependent activation of PPAR{gamma}. Our findings provide structural insight into published in vitro and cellular studies that reported interdomain functional communication between the PPAR{gamma} AF-1 and LBD suggesting some of these effects may be mediated via AF-1/LBD interactions.

biochemistry↗

bioRxiv2021

Conformational Changes of RORγ During Response Element Recognition and Coregulator Engagement.

The retinoic acid receptor-related orphan receptor {gamma} (ROR{gamma}) is a ligand-dependent transcription factor of the nuclear receptor super family that underpins metabolic activity, immune function, and cancer progression. Despite being a valuable drug target in health and disease, our understanding of the ligand-dependent activities of ROR{gamma} is far from complete. Like most nuclear receptors, ROR{gamma} must recruit coregulatory protein to enact the ROR{gamma} target gene program. To date, a majority of structural studies have been focused exclusively on the ROR{gamma} ligand-binding domain and the ligand-dependent recruitment of small peptide segments of coregulators. Herein, we examine the ligand-dependent assembly of full length ROR{gamma}:coregulator complexes on cognate DNA response elements using structural proteomics and small angle x-ray scattering. The results from our studies suggest that ROR{gamma} becomes elongated upon DNA recognition, preventing long range interdomain crosstalk. We also determined that the DNA binding domain adopts a sequence-specific conformation, and that coregulatory proteins may be able to sense the ligand- and DNA-bound status of ROR{gamma}. We propose a model where ligand-dependent coregulator recruitment may be influenced by the sequence of the DNA to which ROR{gamma} is bound. Overall, the efforts described herein will illuminate important aspects of full length ROR{gamma} and monomeric orphan nuclear receptor target gene regulation through DNA-dependent conformational changes. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=81 SRC="FIGDIR/small/445650v1_ufig1.gif" ALT="Figure 1"> View larger version (29K): org.highwire.dtl.DTLVardef@1f0a067org.highwire.dtl.DTLVardef@b2e9f6org.highwire.dtl.DTLVardef@1e15d5org.highwire.dtl.DTLVardef@12b8546_HPS_FORMAT_FIGEXP M_FIG C_FIG

biophysics↗

bioRxiv2019

HDX-MS reveals structural determinants for RORγ hyperactivation by synthetic agonists

Members of the nuclear receptor (NR) superfamily regulate both physiological and pathophysiological processes ranging from development and metabolism1 to inflammation2 and cancer3. As ligand-gated transcription factors, synthetic small molecules targeting NRs are often deployed as therapeutics to correct aberrant NR signaling or as chemical probes to explore the role of the receptor in physiology4. However, nearly half of NRs do not have specific cognate ligands or its unclear if they possess ligand dependent activities and these receptors are called orphans. Here we demonstrate that ligand-dependent action of the orphan nuclear receptor ROR{gamma} can be defined by selectively disrupting putative endogenous--but not synthetic--ligand binding. Furthermore, the characterization of a library of ROR{gamma} modulators reveals that structural dynamics of the receptor assessed by HDX-MS correlate with activity in biochemical and cell-based assays. These findings are corroborated with X-ray co-crystallography and site-directed mutagenesis to collectively reveal the structural determinants of ROR{gamma} ligand-dependent activation, critical for designing full agonists for application in cancer immunotherapy. Combined these observations support a model of receptor activation to more accurately describe ROR{gamma} pharmacology. Likewise, this bump-and-hole inspired approach could be extended to other orphan NRs to explore the ligand-dependent activities that are important for defining pharmacology.

biophysics↗