title: Csk-binding protein controls red blood cell development via regulation of Lyn tyrosine kinase activity.
abstract: Erythropoiesis is controlled principally through erythropoietin (Epo) receptor signaling, which involves Janus kinase 2 (JAK2) and Lyn tyrosine kinase, both of which are important for regulating red blood cell (RBC) development. Negative regulation of Lyn involves C-Src kinase (Csk)-mediated phosphorylation of its C-terminal tyrosine, which is facilitated by the transmembrane adaptor Csk-binding protein (Cbp). Although Cbp has significant functions in controlling Lyn levels and activity in erythroid cells in vitro, its importance to primary erythroid cell development and signaling has remained unclear. To address this, we assessed the consequence of loss of Cbp on the erythroid compartment in vivo and whether Epo-responsive cells isolated from Cbp-knockout mice exhibited altered signaling. Our data show that male Cbp-/-mice display a modest but significant alteration to late erythroid development in bone marrow with evidence of increased erythrocytes in the spleen, whereas female Cbp-/-mice exhibit a moderate elevation in early erythroid progenitors (not seen in male mice) that does not influence the later steps in RBC development. In isolated primary erythroid cells and cell lines generated from Cbp-/-mice, survival signaling through Lyn/Akt/FoxO3 was elevated, resulting in sustained viability during differentiation. The high Akt activity disrupted GAB2/SHP-2 feedback inhibition of Lyn; however, the elevated Lyn activity also increased inhibitory signaling via SHP-1 to restrict the Erk1/2 pathway. Interestingly, whereas loss of Cbp led to mild changes to late RBC development in male mice, this was not apparent in female Cbp-/-mice, possibly due to their elevated estrogen, which is known to facilitate early progenitor self-renewal.
authors.affiliation: Cell Signalling Group, Laboratory for Cancer Medicine, Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Perth, WA, Australia.
authors.forename: Janice H C
authors.initials: JH
authors.lastname: Plani-Lam
authors.affiliation: Cell Signalling Group, Laboratory for Cancer Medicine, Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Perth, WA, Australia.
authors.forename: Neli S
authors.initials: NS
authors.lastname: Slavova-Azmanova
authors.affiliation: Cell Signalling Group, Laboratory for Cancer Medicine, Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Perth, WA, Australia.
authors.forename: Nicole
authors.initials: N
authors.lastname: Kucera
authors.affiliation: Cell Signalling Group, Laboratory for Cancer Medicine, Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Perth, WA, Australia.
authors.forename: Alison
authors.initials: A
authors.lastname: Louw
authors.affiliation: Cell Signalling Group, Laboratory for Cancer Medicine, Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Perth, WA, Australia.
authors.forename: Jiulia
authors.initials: J
authors.lastname: Satiaputra
authors.affiliation: Laboratory of Immunology, Bioprocessing Technology Institute, Agency for Science, Technology and Research, Singapore, Singapore.
authors.forename: Peter
authors.initials: P
authors.lastname: Singer
authors.affiliation: Laboratory of Immunology, Bioprocessing Technology Institute, Agency for Science, Technology and Research, Singapore, Singapore.
authors.forename: Kong-Peng
authors.initials: KP
authors.lastname: Lam
authors.affiliation: Leukocyte Signalling Laboratory, Department of Immunology, Alfred Medical Research and Education Precinct, Monash University, Melbourne, VIC, Australia.
authors.forename: Margaret L
authors.initials: ML
authors.lastname: Hibbs
authors.affiliation: Cell Signalling Group, Laboratory for Cancer Medicine, Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Perth, WA, Australia. Electronic address: evan.ingley@uwa.edu.au.
authors.forename: Evan
authors.initials: E
authors.lastname: Ingley
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000235:genetics; D002460:Cell Line; D002470:Cell Survival / Q000235:genetics; D004789:Enzyme Activation; D041905:Erythroid Cells / Q000166:cytology* / Q000378:metabolism*; D004920:Erythropoiesis; D005260:Female; D000071316:Forkhead Box Protein O3 / Q000378:metabolism; D008297:Male; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D008954:Models, Biological; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6 / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D015398:Signal Transduction; D019061:src-Family Kinases / Q000378:metabolism*
chemical_list: D000071316:Forkhead Box Protein O3; D008565:Membrane Proteins; C498709:Pag1 protein, mouse; D010750:Phosphoproteins; C060902:lyn protein-tyrosine kinase; D019061:src-Family Kinases; D051057:Proto-Oncogene Proteins c-akt; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; C509248:Ptpn6 protein, mouse