Table 1. Histidine Kinase-like Proteins of Arabidopsis

Gene Names	Chrom. Locus^-a	Accession No. (cDNA)^-b	Features^-c	Function	References
ETR1	At1g66340	L24119	HK, Rec	Ethylene Receptor Family	Chang et al. 1993
ETR2	At3g23150	AF047975	Diverged-HK, Rec	Ethylene Receptor Family	Sakai et al. 1998
ERS1	At2g40940	U21952	HK	Ethylene Receptor Family	Hua et al. 1995
ERS2	At1g04310	AF047976	Diverged-HK	Ethylene Receptor Family	Hua et al. 1998
EIN4	At3g04580	AF048982	Diverged-HK, Rec	Ethylene Receptor Family	Hua et al. 1998
WOL1/CRE1/AHK4	At2g01830	AB049934	HK, Rec	Cytokinin Receptor Family	Mähönen et al. 2000; Inoue et al. 2001; Suzuki et al. 2001
AHK2	At5g35750	AB046869	HK, Rec	Cytokinin Receptor Family	Ueguchi et al. 2001
AHK3	At1g27320	AB046870	HK, Rec	Cytokinin Receptor Family	Ueguchi et al. 2001
CKI1	At2g47430	D87545	HK, Rec		Kakimoto, 1996
AtHK1	At2g17820	AB010914	HK, Rec	Putative Osmosensor	Urao et al. 1999
CKI2	At5g10720		HK, Rec		Kakimoto, 1996
PHYA	At1g09570	X17341	Diverged-HK	Phytochrome Family	Sharrock and Quail, 1989
PHYB	At2g18790	X17342	Diverged-HK	Phytochrome Family	Sharrock and Quail, 1989
PHYC	At5g35840	X17343	Diverged-HK	Phytochrome Family	Sharrock and Quail, 1989
PHYD	At4g16250	X76609	Diverged-HK	Phytochrome Family	Clack et al. 1994
PHYE	At4g18130	X76610	Diverged-HK	Phytochrome Family	Clack et al. 1994
PDK	At3g06483	AF039406	Diverged-HK	Pyruvate Dehydrogenase Kinase	Thelen et al. 2000

^-a Chromosome loci are given by the MIPS designation.

^-b Accession numbers are for full-length cDNA sequences reported in the literature.

^-c Features noted are conserved histidine-kinase domain (HK), diverged histidine-kinase domain (Diverged-HK), and receiver domain (Rec).