title: Identification of Tpr and α-actinin-4 as two novel SLK-interacting proteins.
abstract: Expression and activity of the Ste20-like kinase, SLK, are increased during kidney development and recovery from ischemia-reperfusion injury. SLK mediates apoptosis in various cells, and can regulate cell cycle progression and cytoskeletal remodeling. In cells, SLK is detected in a high molecular mass complex, suggesting that SLK is a dimer/oligomer, or is in tight association with other proteins. To better understand the regulation, localization and function of SLK, we sought to identify proteins in this high molecular mass complex. Analysis by mass spectroscopy identified the nucleoporin, translocated promoter region (Tpr), and the cytoskeletal protein, α-actinin-4, as potential SLK-interacting proteins. Using a protein complementation assay, we showed that the 350 amino acid C-terminal, coiled-coil domain of SLK was responsible for homodimerization, as well as interaction with Tpr and α-actinin-4. The association of SLK with Tpr and α-actinin-4, respectively, was confirmed by co-immunoprecipitation. Subsets of total cellular SLK colocalized with Tpr at the nuclear envelope, and α-actinin-4 in the cytoplasm. Expression of Tpr attenuated activation-specific autophosphorylation of SLK, and blocked SLK-induced apoptosis and AP-1 activity. In contrast to the effect of Tpr, autophosphorylation of SLK was not affected by α-actinin-4. Thus, SLK interacts with Tpr and α-actinin-4 in cells, and these protein-protein interactions may control the subcellular localization and the biological activity of SLK.
authors.affiliation: Department of Medicine, McGill University Health Centre, McGill University, Montreal, Quebec H4A 3J1, Canada.
authors.forename: Aala
authors.initials: A
authors.lastname: Jaberi
authors.affiliation: Department of Medicine, McGill University Health Centre, McGill University, Montreal, Quebec H4A 3J1, Canada.
authors.forename: Erika
authors.initials: E
authors.lastname: Hooker
authors.affiliation: Department of Medicine, McGill University Health Centre, McGill University, Montreal, Quebec H4A 3J1, Canada.
authors.forename: Julie
authors.initials: J
authors.lastname: Guillemette
authors.affiliation: Department of Medicine, McGill University Health Centre, McGill University, Montreal, Quebec H4A 3J1, Canada.
authors.forename: Joan
authors.initials: J
authors.lastname: Papillon
authors.affiliation: Department of Medicine, McGill University Health Centre, McGill University, Montreal, Quebec H4A 3J1, Canada.
authors.forename: Arnold S
authors.initials: AS
authors.lastname: Kristof
authors.affiliation: Department of Medicine, McGill University Health Centre, McGill University, Montreal, Quebec H4A 3J1, Canada.. Electronic address: andrey.cybulsky@mcgill.ca.
authors.forename: Andrey V
authors.initials: AV
authors.lastname: Cybulsky
mesh_terms: D000185:Actinin / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D006801:Humans; D028861:Nuclear Pore Complex Proteins / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation / Q000502:physiology; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D021381:Protein Transport / Q000502:physiology; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D000099317:Hippo Kinases
chemical_list: D000185:Actinin; D028861:Nuclear Pore Complex Proteins; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; C111453:ACTN4 protein, human; C073597:TPR protein, human; C485733:SLK protein, human; D000099317:Hippo Kinases
keywords: Fluorescence; Phosphorylation; Protein complementation assay; Protein kinases; Protein–protein interactions; Subcellular organelles