title: "Tie-ing" down the hematopoietic niche.
abstract: Interaction of hematopoietic stem cells (HSCs) with their particular microenvironment, or niche, is critical for adult hematopoiesis in the bone marrow (BM). Arai et al. (this issue of Cell) demonstrate that HSCs that express the receptor tyrosine kinase Tie2 are quiescent. Ang-1, the ligand for Tie2, enhanced the ability of HSCs to become quiescent and also induced their adhesion to bone, protecting them from stresses that suppress hematopoiesis. These data suggest that the Ang-1/Tie2 signaling pathway plays a crucial role in the maintenance of HSCs in a quiescent state in the BM niche.
authors.affiliation: Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
authors.forename: Kateri A
authors.initials: KA
authors.lastname: Moore
authors.forename: Ihor R
authors.initials: IR
authors.lastname: Lemischka
mesh_terms: D042683:Angiopoietin-1 / Q000378:metabolism*; D000818:Animals; D002448:Cell Adhesion / Q000502:physiology; D002450:Cell Communication / Q000502:physiology; D002454:Cell Differentiation / Q000502:physiology; D002455:Cell Division / Q000502:physiology; D006410:Hematopoiesis / Q000502:physiology*; D006412:Hematopoietic Stem Cells / Q000201:enzymology*; D006801:Humans; D042787:Receptor, TIE-2 / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*
chemical_list: D042683:Angiopoietin-1; D042787:Receptor, TIE-2