title: The Src-like adaptor protein 2 regulates colony-stimulating factor-1 receptor signaling and down-regulation.
abstract: Src-like adaptor protein 2 (SLAP-2) is a hematopoietic adaptor protein previously implicated as a negative regulator of T-cell antigen receptor (TCR)-mediated signaling. SLAP-2 contains an SH3 and an SH2 domain, followed by a unique carboxyl-terminal tail, which is important for c-Cbl binding. Here we describe a novel role for SLAP-2 in regulation of the colony-stimulating factor 1 receptor (CSF-1R), a receptor tyrosine kinase important for growth and differentiation of myeloid cells. SLAP-2 co-immunoprecipitates with c-Cbl and CSF-1R in primary bone marrow-derived macrophages. Using murine myeloid cells expressing CSF-1R (FD-Fms cells), we show that SLAP-2 is tyrosine-phosphorylated upon stimulation with CSF-1 and associates constitutively with both c-Cbl and CSF-1R. In addition, we show that expression of a dominant negative form of SLAP-2 impairs c-Cbl association with the CSF-1R and receptor ubiquitination. Impaired c-Cbl recruitment also correlated with changes in the kinetics of CSF-1R down-regulation and trafficking. CSF-1-mediated differentiation of FD-Fms cells and activation of downstream signaling events was also enhanced in cells stably expressing dominant negative SLAP-2. Together, these results demonstrate that SLAP-2 plays a role in c-Cbl-dependent down-regulation of CSF-1R signaling.
authors.affiliation: Department of Medical Biophysics, University of Toronto, Hospital for Sick Children, Toronto, Ontario M5G 1L7, Canada; The Arthur and Sonia Labatt Brain Tumour Research Centre, Hospital for Sick Children, Toronto, Ontario M5G 1L7, Canada.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Pakuts
authors.affiliation: The Arthur and Sonia Labatt Brain Tumour Research Centre, Hospital for Sick Children, Toronto, Ontario M5G 1L7, Canada.
authors.forename: Christophe
authors.initials: C
authors.lastname: Debonneville
authors.affiliation: Department of Medical Biophysics, University of Toronto, Hospital for Sick Children, Toronto, Ontario M5G 1L7, Canada; The Arthur and Sonia Labatt Brain Tumour Research Centre, Hospital for Sick Children, Toronto, Ontario M5G 1L7, Canada.
authors.forename: Larissa M
authors.initials: LM
authors.lastname: Liontos
authors.affiliation: Department of Medical Biophysics, University of Toronto, Hospital for Sick Children, Toronto, Ontario M5G 1L7, Canada; The Arthur and Sonia Labatt Brain Tumour Research Centre, Hospital for Sick Children, Toronto, Ontario M5G 1L7, Canada.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Loreto
authors.affiliation: Department of Medical Biophysics, University of Toronto, Hospital for Sick Children, Toronto, Ontario M5G 1L7, Canada; The Arthur and Sonia Labatt Brain Tumour Research Centre, Hospital for Sick Children, Toronto, Ontario M5G 1L7, Canada. Electronic address: jmcglade@sickkids.ca.
authors.forename: C Jane
authors.initials: CJ
authors.lastname: McGlade
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism* / Q000502:physiology*; D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology / Q000378:metabolism; D015536:Down-Regulation; D005786:Gene Expression Regulation; D008264:Macrophages / Q000166:cytology; D051379:Mice; D010766:Phosphorylation; D011485:Protein Binding; D050721:Proto-Oncogene Proteins c-cbl / Q000378:metabolism*; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000378:metabolism* / Q000502:physiology*; D016186:Receptor, Macrophage Colony-Stimulating Factor / Q000378:metabolism*; D015398:Signal Transduction; D025801:Ubiquitin / Q000378:metabolism; D018909:src Homology Domains
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C441328:SLA2 protein, human; D025801:Ubiquitin; D050721:Proto-Oncogene Proteins c-cbl; D016186:Receptor, Macrophage Colony-Stimulating Factor; D016392:Proto-Oncogene Proteins pp60(c-src)