Cyanobacterial glucokinase complements the glucose sensing role of Arabidopsis thaliana hexokinase 1.
Unlike Arabidopsis hexokinase (AtHXK) 1, cyanobacterial glucokinase (cGlk, Sll0593) from Synechocystis sp. PCC6803 does not function endogenously as a glucose sensor for glucose repression of photosynthesis-related genes such as psbA2, psbD2, rbcS, and rbcL. However, when cGlk was constitutively expressed in the cytosol of the glucose insensitive AtHXK 1 null mutant gin2-1, transgenic plants showed glucose sensitive phenotypes similar to those of wild type plants, namely glucose-induced decreases in Chl content and transcript levels of genes encoding Chl binding proteins (CAB1) and Rubisco small subunit (RBCS). Therefore, we suggest that cGlk's ability to complement glucose sensing activity in higher plants is attributable to the presence of cGlk-interacting proteins present in Arabidopsis, but absent in Synechocystis.
Ryu
Jee-Youn
JY
School of Bioscience and Biotechnology, Chungnam National University, Gungdong 220, Youseong, Daejeon 305-764, Republic of Korea.
Jeong
Seok-Won
SW
Kim
Soo Youn
SY
Ko
Yoonae
Y
Yoon
Sukjoon
S
Choi
Sang-Bong
SB
Park
Youn-Il
YI
D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D018389:Codon, Nonsense; D005816:Genetic Complementation Test; D005941:Glucokinase / Q000235:genetics / Q000378:metabolism*; D005947:Glucose / Q000235:genetics / Q000378:metabolism*; D006593:Hexokinase / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D010641:Phenotype; D030821:Plants, Genetically Modified / Q000201:enzymology / Q000235:genetics; D011487:Protein Conformation; D046939:Synechocystis / Q000235:genetics / Q000378:metabolism*
D029681:Arabidopsis Proteins; D001426:Bacterial Proteins; D018389:Codon, Nonsense; D006593:Hexokinase; C473630:ATHXK1 protein, Arabidopsis; D005941:Glucokinase; D005947:Glucose