A potential role for the Src-like adapter protein SLAP-2 in signaling by the colony stimulating factor-1 receptor.
The development of macrophages from myeloid progenitor cells is primarily controlled by the growth factor colony stimulating factor-1 (CSF-1) and its cognate receptor, a transmembrane tyrosine kinase encoded by the c-Fms proto-oncogene. The CSF-1 receptor exerts its biological effects on cells via a range of signaling proteins including Erk1/2 and Akt. Here we have investigated the potential involvement of the Src-like adapter protein (SLAP-2) in signaling by the CSF-1 receptor in mouse bone marrow-derived macrophages. RT-PCR analysis revealed constitutive expression of the SLAP-2 gene in bone marrow macrophages. Surprisingly, co-immunoprecipitation and GST binding experiments demonstrated that the CSF-1 receptor could bind to SLAP-2 in a ligand-independent manner. Furthermore, the binding of SLAP-2 to the CSF-1 receptor involved multiple domains of SLAP-2. SLAP-2 also bound c-Cbl, with the interaction being mediated, at least in part, by the unique C-terminal domain of SLAP-2. Overexpression of SLAP-2 in bone marrow macrophages partially suppressed the CSF-1-induced tyrosine phosphorylation and/or expression level of a approximately 80 kDa protein without affecting CSF-1-induced global tyrosine phosphorylation, or activation of Akt or Erk1/2. Significantly, CSF-1 stimulation induced serine phosphorylation of SLAP-2. Pharmacologic inhibition of specific protein kinases revealed that CSF-1-induced phosphorylation of SLAP-2 was dependent on JNK activity. Taken together, our results suggest that SLAP-2 could potentially be involved in signaling by the CSF-1 receptor.
Manes
Gael A
GA
Department of Medicine and Cooperative Research Centre for Chronic Inflammatory Diseases, The University of Melbourne, Royal Melbourne Hospital, Victoria, Australia.
Masendycz
Paul
P
Nguyen
Thao
T
Achuthan
Adrian
A
Dinh
Hang
H
Hamilton
John A
JA
Scholz
Glen M
GM
D000595:Amino Acid Sequence; D000818:Animals; D001853:Bone Marrow / Q000378:metabolism; D005260:Female; D006801:Humans; D007668:Kidney / Q000378:metabolism; D008024:Ligands; D048670:MAP Kinase Kinase 4 / Q000378:metabolism; D016173:Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D008264:Macrophages / Q000166:cytology / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D008969:Molecular Sequence Data; D010766:Phosphorylation; D000090063:Proto-Oncogene Mas; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics / Q000378:metabolism; D050721:Proto-Oncogene Proteins c-cbl / Q000235:genetics / Q000378:metabolism; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000235:genetics / Q000378:metabolism*; D016186:Receptor, Macrophage Colony-Stimulating Factor / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D012694:Serine / Q000737:chemistry / Q000378:metabolism; D015398:Signal Transduction; D014443:Tyrosine
D008024:Ligands; C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; C095148:Sla protein, mouse; D014443:Tyrosine; D012694:Serine; D016173:Macrophage Colony-Stimulating Factor; D050721:Proto-Oncogene Proteins c-cbl; D016186:Receptor, Macrophage Colony-Stimulating Factor; D016392:Proto-Oncogene Proteins pp60(c-src); D051057:Proto-Oncogene Proteins c-akt; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D048670:MAP Kinase Kinase 4