CHRK1, a chitinase-related receptor-like kinase in tobacco.
A cDNA encoding a chitinase-related receptor-like kinase, designated CHRK1, was isolated from tobacco (Nicotiana tabacum). The C-terminal kinase domain (KD) of CHRK1 contained all of the conserved amino acids of serine/threonine protein kinases. The putative extracellular domain was closely related to the class V chitinase of tobacco and to microbial chitinases. CHRK1 mRNA accumulation was strongly stimulated by infection with fungal pathogen and tobacco mosaic virus. Amino acid-sequence analysis revealed that the chitinase-like domain of CHRK1 lacked the essential glutamic acid residue required for chitinase activity. The recombinant chitinase-like domain did not show any catalytic activity for either oligomeric or polymeric chitin substrates. The recombinant KD of CHRK1 exhibited autophosphorylation, but the mutant KD with a mutation in the essential ATP-binding site did not, suggesting that CHRK1 encoded a functional kinase. CHRK1 was detected in membrane fractions of tobacco BY2 cells. Furthermore, CHRK1-GFP fusion protein was localized in plasma membranes when it was expressed in animal cells. This is the first report of a new type of receptor-like kinase containing a chitinase-like sequence in the putative extracellular domain.
Kim
Y S
YS
Plant Cell Biotechnology Laboratory, Korea Research Institute of Bioscience and Biotechnology, P.O. Box 115, Yusong, Taejon 305-600, Korea.
Lee
J H
JH
Yoon
G M
GM
Cho
H S
HS
Park
S W
SW
Suh
M C
MC
Choi
D
D
Ha
H J
HJ
Liu
J R
JR
Pai
H S
HS
D000595:Amino Acid Sequence; D015139:Blotting, Southern; D049452:Green Fluorescent Proteins; D006367:HeLa Cells; D006801:Humans; D015151:Immunoblotting; D008164:Luminescent Proteins / Q000235:genetics; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D010766:Phosphorylation; D010838:Phytophthora; D010940:Plant Proteins; D010947:Plants, Toxic; D017346:Protein Serine-Threonine Kinases / Q000235:genetics* / Q000378:metabolism; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D014026:Nicotiana / Q000201:enzymology* / Q000235:genetics / Q000382:microbiology; D014027:Tobacco Mosaic Virus
D008164:Luminescent Proteins; D008565:Membrane Proteins; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; C414309:CHRK1 protein, Nicotiana tabacum; D017346:Protein Serine-Threonine Kinases