title: Evidence for intermolecular interactions between the intracellular domains of the arabidopsis receptor-like kinase ACR4, its homologs and the Wox5 transcription factor.
abstract: Arabidopsis CRINKLY4 (ACR4) is a receptor-like kinase (RLK) involved in the global development of the plant. The Arabidopsis genome encodes four homologs of ACR4 that contain sequence similarity and analogous architectural elements to ACR4, termed Arabidopsis CRINKLY4 Related (AtCRRs) proteins. Additionally, a signaling module has been previously proposed including a postulated peptide ligand, CLE40, the ACR4 RLK, and the WOX5 transcription factor that engage in a possible feedback mechanism controlling stem cell differentiation. However, little biochemical evidence is available to ascertain the molecular aspects of receptor heterodimerization and the role of phosphorylation in these interactions. Therefore, we have undertaken an investigation of the in vitro interactions between the intracellular domains (ICD) of ACR4, the CRRs and WOX5. We demonstrate that interaction can occur between ACR4 and all four CRRs in the unphosphorylated state. However, phosphorylation dependency is observed for the interaction between ACR4 and CRR3. Furthermore, sequence analysis of the ACR4 gene family has revealed a conserved 'KDSAF' motif that may be involved in protein-protein interactions among the receptor family. We demonstrate that peptides harboring this conserved motif in CRR3 and CRK1are able to bind to the ACR4 kinase domain. Our investigations also indicate that the ACR4 ICD can interact with and phosphorylate the transcription factor WOX5.
authors.affiliation: Department of Medicine, Washington University School of Medicine, 660 S. Euclid Ave, St. Louis, MO 63130, United States of America.
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Meyer
authors.affiliation: Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa 50011, United States of America.
authors.forename: Shweta
authors.initials: S
authors.lastname: Shah
authors.affiliation: NIH NCRR Center for Biomedical and Bio-Organic Mass Spectrometry, Dept. of Chemistry, Washington University, St. Louis, MO 63130, United States of America.
authors.forename: J
authors.initials: J
authors.lastname: Zhang
authors.affiliation: NIH NCRR Center for Biomedical and Bio-Organic Mass Spectrometry, Dept. of Chemistry, Washington University, St. Louis, MO 63130, United States of America.
authors.forename: Henry
authors.initials: H
authors.lastname: Rohrs
authors.affiliation: Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa 50011, United States of America.
authors.forename: A Gururaj
authors.initials: AG
authors.lastname: Rao
mesh_terms: D017360:Arabidopsis / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D050746:Dihydrodipicolinate Reductase / Q000737:chemistry / Q000378:metabolism; D018398:Homeodomain Proteins / Q000737:chemistry* / Q000378:metabolism*; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D010766:Phosphorylation; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry* / Q000378:metabolism*; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011956:Receptors, Cell Surface / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; C518087:CRR3 protein, Arabidopsis; D018398:Homeodomain Proteins; D008565:Membrane Proteins; D011956:Receptors, Cell Surface; C116421:WUSCHEL protein, Arabidopsis; D050746:Dihydrodipicolinate Reductase; C462019:ACR4 protein, Arabidopsis; C525931:CRR1 protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases