INTERACTION OF A PROTEIN PHOSPHATASE WITH AN ARABIDOPSIS SERINE-THREONINE RECEPTOR KINASE

A protein phosphatase was cloned that interacts with a serine-threonin e receptor-like kinase, RLK5, from Arabidopsis thaliana. The phosphata se, designated KAPP (kinase-associated protein phosphatase), is compos ed of three domains: an amino-terminal signal anchor, a kinase interac tion (KI) domain, and a type 2C protein phosphatase catalytic region. Association of RLK5 with the KI domain is dependent on phosphorylation of RLK5 and can be abolished by dephosphorylation. KAPP may function as a signaling component in a pathway involving RLK5.