title: SWAP-70 regulates erythropoiesis by controlling α4 integrin.
abstract: Background The regulation of normal and stress-induced erythropoiesis is incompletely understood. Integrin-dependent adhesion plays important roles in erythropoiesis, but how integrins are regulated during erythropoiesis remains largely unknown.
  
  
  METHODS
  To obtain novel insights into the regulation of erythropoiesis, we used cellular and molecular approaches to analyze the role of SWAP-70 and the control of integrins through SWAP-70. In addition, mice deficient for this protein were investigated under normal and erythropoietic stress conditions.
  
  
  RESULTS
  We show that SWAP-70, a protein involved in cytoskeletal F-actin rearrangements and integrin regulation in mast cells, is expressed in hematopoietic stem cells and myeloid-erythroid precursors. Although Swap-70(-/-) mice are not anemic, erythroblastic differentiation is perturbed, and SWAP-70 is required for an efficient erythropoietic stress response to acute anemia and for erythropoietic recovery after bone marrow transplantation in irradiated mice. SWAP-70 deficiency impairs colony-forming unit erythroid development, while burst-forming unit erythroid development is normal, and significantly affects development of late erythroblasts in the spleen and bone marrow. The α(4) integrin is constitutively hyper-activated in Swap-70(-/-) colony-forming unit erythroid cells, which hyper-adhere to fibronectin. Blocking α(4) and β(1) integrin chains in vivo restored erythroblastic differentiation and the erythropoietic stress response in Swap-70(-/-) mice.  Conclusions Our study reveals that SWAP-70 is a novel regulator of integrin-mediated red blood cell development and stress-induced erythropoiesis.
authors: Institute of Physiological Chemistry, Dresden University of Technology Fiedlerstr. 42, Dresden, Germany.
authors: Tatsiana
authors: T
authors: Ripich
authors: Rolf
authors: R
authors: Jessberger
mesh_terms: D000199:Actins / Q000235:genetics / Q000378:metabolism; D000740:Anemia / Q000235:genetics / Q000378:metabolism; D000818:Animals; D002448:Cell Adhesion / Q000502:physiology; D002454:Cell Differentiation / Q000502:physiology*; D003599:Cytoskeleton / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004900:Erythroblasts / Q000166:cytology / Q000378:metabolism*; D004920:Erythropoiesis / Q000502:physiology*; D005353:Fibronectins / Q000235:genetics / Q000378:metabolism; D020662:Guanine Nucleotide Exchange Factors / Q000235:genetics / Q000378:metabolism*; D039441:Integrin alpha4 / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D015778:Minor Histocompatibility Antigens; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D000199:Actins; D004268:DNA-Binding Proteins; D005353:Fibronectins; D020662:Guanine Nucleotide Exchange Factors; D015778:Minor Histocompatibility Antigens; D009687:Nuclear Proteins; C113365:Swap70 protein, mouse; D039441:Integrin alpha4