TABLE 4.

Osmotically activated osmoprotectant transporters^a

Transporter class	Transporter name	Organism	Activatorb		Sequence known	Reference
			I	NI
ABC transporter	ProU	Escherichia coli	Yes	Yes	Yes	68
	Not assigned	Listeria monocytogenes	Yes	NT	No	283
Ion symporter	ProP	Escherichia coli	Yes	Yes	Yes	84
		Salmonella typhimurium	Yes	NT	No	31
	BetT	Escherichia coli	Yes	NT	Yes	264
	Not assigned	Staphylococcus aureus	Yes	Yes	No	222
	OpuD	Bacillus subtilis	Yes	NT	Yes	113
	BetP	Corynebacterium glutamicum	Yes	Yes	Yes	213
	Not assigned	Listeria monocytogenes	Yes	Yes	No	79

^aThe listed transporters were activated by an osmotic upshift imposed with at least one ionic or nonionic cosolvent in the absence of protein synthesis. 

^bI, ionic; NI, nonionic; NT, not tested.