title: Sphingosine kinase 1 isoform-specific interactions in breast cancer.
abstract: Sphingosine kinase 1 (SK1) is a signaling enzyme that catalyzes the formation of sphingosine-1-phosphate. Overexpression of SK1 is causally associated with breast cancer progression and resistance to therapy. SK1 inhibitors are currently being investigated as promising breast cancer therapies. Two major transcriptional isoforms, SK143 kDa and SK151 kDa, have been identified; however, the 51 kDa variant is predominant in breast cancer cells. No studies have investigated the protein-protein interactions of the 51 kDa isoform and whether the two SK1 isoforms differ significantly in their interactions. Seeking an understanding of the regulation and role of SK1, we used a triple-labeling stable isotope labeling by amino acids in cell culture-based approach to identify SK1-interacting proteins common and unique to both isoforms. Of approximately 850 quantified proteins in SK1 immunoprecipitates, a high-confidence list of 30 protein interactions with each SK1 isoform was generated via a meta-analysis of multiple experimental replicates. Many of the novel identified SK1 interaction partners such as supervillin, drebrin, and the myristoylated alanine-rich C-kinase substrate-related protein supported and highlighted previously implicated roles of SK1 in breast cancer cell migration, adhesion, and cytoskeletal remodeling. Of these interactions, several were found to be exclusive to the 43 kDa isoform of SK1, including the protein phosphatase 2A, a previously identified SK1-interacting protein. Other proteins such as allograft inflammatory factor 1-like protein, the latent-transforming growth factor β-binding protein, and dipeptidyl peptidase 2 were found to associate exclusively with the 51 kDa isoform of SK1. In this report, we have identified common and isoform-specific SK1-interacting partners that provide insight into the molecular mechanisms that drive SK1-mediated oncogenicity.
authors.affiliation: School of Biotechnology and Biomolecular Sciences (D.Y., M.R.W.), University of New South Wales, Sydney 2052, Australia; Centenary Institute (D.Y., A.L., D.G.K., P.X., E.M.M.), Sydney 2042, Australia; Translational Cancer Research Group (D.H., R.M.-W., E.M.M.), Faculty of Science, School of Medical and Molecular Biosciences, and Faculty of Engineering and Information Technology (S.B., G.H.), University of Technology Sydney, Sydney, New South Wales 2007, Australia; Department of Biochemistry (J.H.L., W.W.), Tufts University School of Medicine, Boston, Massachusetts 02111; Shanghai Medical School (P.X.), Fudan University, 200433 Shanghai, People's Republic of China; and Sydney Medical School (E.M.M.), The University of Sydney, Sydney 2006, Australia.
authors.forename: Daniel
authors.initials: D
authors.lastname: Yagoub
authors.forename: Marc R
authors.initials: MR
authors.lastname: Wilkins
authors.forename: Angelina J
authors.initials: AJ
authors.lastname: Lay
authors.forename: Dominik C
authors.initials: DC
authors.lastname: Kaczorowski
authors.forename: Diana
authors.initials: D
authors.lastname: Hatoum
authors.forename: Sarah
authors.initials: S
authors.lastname: Bajan
authors.forename: Gyorgy
authors.initials: G
authors.lastname: Hutvagner
authors.forename: Jack H
authors.initials: JH
authors.lastname: Lai
authors.forename: Wengen
authors.initials: W
authors.lastname: Wu
authors.forename: Rosetta
authors.initials: R
authors.lastname: Martiniello-Wilks
authors.forename: Pu
authors.initials: P
authors.lastname: Xia
authors.forename: Eileen M
authors.initials: EM
authors.lastname: McGowan
mesh_terms: D001943:Breast Neoplasms / Q000378:metabolism*; D002135:Calcium-Binding Proteins; D002448:Cell Adhesion / Q000502:physiology; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000502:physiology; D004268:DNA-Binding Proteins / Q000378:metabolism; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / Q000378:metabolism; D005260:Female; D006801:Humans; D053779:Latent TGF-beta Binding Proteins / Q000378:metabolism; D008246:Lysophospholipids / Q000378:metabolism; D061986:MCF-7 Cells; D008840:Microfilament Proteins; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000378:metabolism*; D020033:Protein Isoforms / Q000378:metabolism*; D015398:Signal Transduction; D013110:Sphingosine / Q000031:analogs & derivatives / Q000378:metabolism; D000099157:Sphingosine Kinase
chemical_list: D002135:Calcium-Binding Proteins; D004268:DNA-Binding Proteins; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases; D053779:Latent TGF-beta Binding Proteins; D008246:Lysophospholipids; D008840:Microfilament Proteins; D017853:Phosphotransferases (Alcohol Group Acceptor); D020033:Protein Isoforms; D013110:Sphingosine; D000099157:Sphingosine Kinase; C112986:AIF1 protein, human; C060506:sphingosine 1-phosphate; C100151:dipeptidyl peptidase II