Arabidopsis SERK1 protein interacts with the AAA-ATPase AtCDC48, the 14-3-3 protein GF14 lambda and the PP2C phosphatase KAPP

Leucine-rich repeat (LRR)-containing transmembrane receptor-like kinases (RLKs) are important components of plant signal transduction. The Arabidopsis thaliana somatic embryogenesis receptor-like kinase 1 (AtSERK1) is an LRR-RLK proposed to participate in a signal transduction cascade involved in embryo development. By yeast two-hybrid screening we identified AtCDC48, a homologue of the mammalian AAA-ATPase p97 and GF14λ, a member of the Arabidopsis family of 14-3-3 proteins as AtSERK1 interactors. In vitro, the AtSERK1 kinase domain is able to transphosphorylate and bind both AtCDC48 and GF14λ. In yeast, AtCDC48 interacts with GF14λ and with the PP2C phosphatase KAPP. In plant protoplasts AtSERK1 interacts with GF14λ.