High impact information on MEKK1

• In Arabidopsis protoplasts, MKK2 was specifically activated by cold and salt stress and by the stress-induced MAPK kinase kinase MEKK1 [1].
• MEKK1 Is Required for MPK4 Activation and Regulates Tissue-specific and Temperature-dependent Cell Death in Arabidopsis [2].
• We show here that MEKK1 is not required for flagellin-triggered activation of MPK3 and MPK6 [2].
• These results suggest the presence of AtMEKK1-AtMEK1 pathway induced by wounding [3].
• We have constructed a series of deletion mutants of Arabidopsis MAPK kinase kinase (AtMEKK1) and obtained a constitutively active mutant, AtMEKK1Delta166, which lacks in self-inhibitory sequence of N-terminal 166 amino acids but still has substrate specificity [3].

Biological context of MEKK1

• Overall, our data defines MPK4 as downstream target of MEKK1 and show that MEKK1 functions in integrating ROS homeostasis with plant development and hormone signaling [4].
• Therefore, we propose that the A. thaliana ATMEKK1 may be a part of the signal transduction pathway involved in osmotic stress [5].
• Characterisation of novel plant genes encoding MEKK/STE11 and RAF-related protein kinases [6].

Associations of MEKK1 with chemical compounds

• MEKK1 kinase activity and protein stability was regulated by H(2)O(2) in a proteasome-dependent manner and mekk1 plants were compromised in ROS-induced MAPK MPK4 activation [4].
• Enhanced glycerol production, observed in non-stressed cells expressing ATMEKK1 is the probable cause of yeast survival [5].

Other interactions of MEKK1

• Coexpression of the N-terminal deletion form of ATMEKK1 increased the ability of MEK1 to suppress a growth defect of the yeast pbs2delta mutant [7].
• In two-hybrid screening using ATMEKK1 as bait, we isolated a novel MAPKK homologue, ATMKK2, a MAPK homologue, ATMPK4, and an unknown protein [8].
• One is the two-hybrid screening of ATMEKK1 (a MAPKKK)-interacting proteins; the other is an analysis of physical and functional interactions among isolated MAPK, MAPKK, and MAPKKK homologues from Arabidopsis [8].

References