Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Target Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Query: EC:3.1.3.16 (
calcineurin
)
17,112
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
CHIP proteins are E3 ubiquitin ligases that promote degradation of Hsp70 and Hsp90 substrate proteins through the 26S proteasome in animal systems. A CHIP-like protein in Arabidopsis, AtCHIP, also has E3 ubiquitin ligase activity and has important roles to play under conditions of abiotic stress. In an effort to study the mode of action of AtCHIP in plant cells, proteins that physically interact with it were identified. Like its animal orthologs, AtCHIP interacts with a unique class of ubiquitin-conjugating enzymes (UBC or E2) that belongs to the stress-inducible
UBC4/5
class in yeast. AtCHIP also interacts with other proteins, including an A subunit of protein phosphatase 2A (
PP2A
). This
PP2A
subunit appears to be a substrate of AtCHIP, because it can be ubiquitylated by AtCHIP in vitro and because the activity of
PP2A
is increased in AtCHIP-overexpressing plants in the dark or under low-temperature conditions. Unlike the rcn1 mutant, that has reduced
PP2A
activity due to a mutation in one of the A subunit genes of
PP2A
, AtCHIP-overexpressing plants are more sensitive to ABA treatment. Since
PP2A
was previously shown to be involved in low-temperature responses in plants, the low-temperature-sensitive phenotype observed in AtCHIP-overexpressing plants might be partly due to the change in
PP2A
activity. These data suggest that the E3 ubiquitin ligase AtCHIP may function upstream of
PP2A
in stress-responsive signal transduction pathways under conditions of low temperature or in the dark.
...
PMID:AtCHIP functions as an E3 ubiquitin ligase of protein phosphatase 2A subunits and alters plant response to abscisic acid treatment. 1664 Jun 1
