Table 1.

IDRS SHOWING FUNCTIONAL RESPONSE TO PHYSICOCHEMICAL CHANGES

Change	Protein	Function/Observation	Reference(s)
CO2	Ptc2 phosphatase	Drives phenotypic (white-opaque) switching in C. albicans	[76]
Water availability/deficit	Hydrophilins, LEA proteins	Protection from water stress	[88][51][88]
	LEA proteins	Sensing of osmotic stress	[33]
	CAHS D	Desiccation protection in tardigrades; acquires helical structure and forms hydrogels upon desiccation	[52–54,89]
	FLOE1	Undergoes phase separation under hydration; signals A. thaliana to suppress germination in unfavorable environments	[90]
	SEUSS	Stress tolerance in A. thaliana; drives localization to condensates in response to hyperosmotic conditions	[91]
Macromolecular crowding	YAP	Transcriptional coactivator in human cell growth that localizes in condensates in response to cell volume decrease and alters expression patterns	[121]
	ASK3	Kinase that forms condensates upon cell volume decrease and regulates volume recovery	[122]
	WNK1	Kinase that forms condensates upon sensing crowding and regulates cell volume	[92]
Redox state	CP12	Regulates the Calvin-Benson-Bassham cycle	[95]
	NPR1	Regulates the ubiquitylation of stress response machinery through biomolecular condensates	[96]
	TMF	Gene control during flower development	[97]
	TDP-43	Proposed to function as intracellular redox sensor	[98]
	Ataxin-2	Proposed to function as intracellular redox sensor	[99]
pH	Snf5	Enables transcriptional rewiring in budding yeast	[80]
	Sup35	May tune local pKa values into the physiological range in yeast	[45]
	HSF1	pH-responsive element involved in yeast stress response	[79]
	G3BP1	Mammalian stress-granule formation	[86]
Ions & metals	ASK3	Na+ regulates the liquidity of ASK3 condensates	[123]
	SK	Disordered regions that fold upon Ca2+ binding	[100]
	SilE	Disordered bacterial protein that folds upon silver binding	[102]
	PrPc	Binds copper via octa-repeat motifs in its disordered N-terminal IDR. This region may also bind other metals.	[103]
	Granulins	Small cysteine-rich disordered proteins that can sequester copper	[104]
	Mms6	Bacterial protein whose C-terminal IDR coordinates iron in the context of magnetosome formation	[105]
	ProTα	Highly-charged IDR that can bind zinc; this binding has been proposed to act as an entropic switch.	[106]
Insulin	SIRT1	An insulin binding motif in the N-terminal IDR leads insulin-dependent structural acquisition	[124]
Temperature	Pab1	Tunes stress granule assembly during heat stress in S. cerevisiae via the P-domain (however, P-domain is not required for condensation)	[44]
	ELF3	A polyglutamine tract in the ELF3 prion-like domain tunes temperature sensing in Arabidopsis	[117]
	FRIGIDA	C-terminal IDR contributes to cold-dependent condensate formation in Arabidopsis	[118]
	Phytochrome B	Encodes molecular timer to tune phytochrome revision in Arabidopsis	[120]