Will, D. | Search bioRxiv

bioRxiv2026

NLRP3 activators disrupt the endocytic AP2 complex and plasma membrane signaling

Organellar perturbations are linked to NLRP3 inflammasome activation, however, it remains unclear whether unrelated agonists converge on a common upstream pathway. Here, we traced intracellular organelle and protein movements by differential ultracentrifugation combined with mass spectrometry-based proteomics. We show that NLRP3 activators uniformly disrupt the endocytic Adaptor Protein 2 (AP2) complex, whereas other subcellular rearrangements are stimulus-specific. We discovered Dynasore as a K-efflux-independent NLRP3 activator that engages this signaling node irrespective of endocytosis inhibition. Pharmacological and genetic perturbation of AP2 renders cells unresponsive to extracellular cues, blunting GPCR signaling, cAMP production, and chemotaxis, thereby enforcing a frozen signaling state that propagates NLRP3 inflammasome activation. Collectively, our study reveals a common surveillance checkpoint linking impaired plasma membrane signaling to the execution of inflammation and cell death. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/707400v1_ufig1.gif" ALT="Figure 1"> View larger version (44K): org.highwire.dtl.DTLVardef@178eb1dorg.highwire.dtl.DTLVardef@193cb02org.highwire.dtl.DTLVardef@1f50080org.highwire.dtl.DTLVardef@1f3e3e4_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗

bioRxiv2026

Electrostatic buffering of non-native interactions in the transition state ensemble for binding of intrinsically disordered proteins

Intrinsically disordered protein regions (IDRs) establish highly specific protein-protein interactions that play key roles in cell signaling. Many IDRs adopt an ordered structure upon binding to folded protein domains, but the energy landscape for coupled folding and binding (CFB) is poorly understood. Here, we elucidate the energy landscape for CFB using the LxCxE motif from the human papillomavirus E7 protein (LxCxEWT) as a minimal model system. Kinetic and structural analysis uncovers strong compensatory energetics whereby stabilizing electrostatic interactions counterbalance energetic frustration in the rate-limiting step for CFB. This mechanism, which we refer to as electrostatic compensation, enables a dynamic search for native contacts while preventing complex dissociation. A global analysis reveals energetic frustration in earliest steps of CFB for many IDRs. Electrostatic compensation may be a widespread mechanism evolved to allow fine-tuning of the affinity and specificity of IDR interactions, which dictates functional selection for charge content within IDRs.

biophysics↗