At4g29810: ATMKK2 (ARABIDOPSIS THALIANA MAP KINASE KINASE 2)

encodes a MAP kinase kinase 2 that regulates MPK6 and MPK4 in response to cold and salt stresses. Co-expression with MEKK1 in protoplasts activated MKK2 activity, suggesting that MEKK1 may be a regulator of MKK2.