Journal
BLOOD
Volume 119, Issue 20, Pages 4625-4635Publisher
AMER SOC HEMATOLOGY
DOI: 10.1182/blood-2011-08-372524
Keywords
-
Categories
Funding
- European Social Fund
- Romanian Government [POSDRU/89/1.5/S/64109/]
- Fonds de la Recherche Scientifique-Fonds National de le Rescherche Scientifique (FRS-FNRS), Belgium (Mandat d'Impulsion and Fonds de la Recherche Scientifique Medicale)
- Salus Sanguinis Foundation
- Action de Recherche Concertee projects of the University Catholique de Louvain, Brussels [MEXP31C1, ARC10/15-027]
- Fondation contre le Cancer, Brussels
- PAI Program, Belgium [BCHM61B5]
- Atlantic Philanthropies, New York
- de Duve Institute fellowship
- FRS-FNRS fellowships
Ask authors/readers for more resources
The constitutively active JAK2 V617F mutant is the major determinant of human myeloproliferative neoplasms (MPNs). We show that coexpression of murine JAK2 V617F and the murine thrombopoietin (Tpo) receptor (TpoR, c-MPL) in hematopoietic cell lines or heterozygous knock-in of JAK2 V617F in mice leads to down-modulation of TpoR levels. Enhanced TpoR ubiquitinylation, proteasomal degradation, reduced recycling, and maturation are induced by the constitutive JAK2 V617F activity. These effects can be prevented in cell lines by JAK2 and proteasome inhibitors. Restoration of TpoR levels by inhibitors could be detected in platelets from JAK2 inhibitor-treated myelofibrosis patients that express the JAK2 V617F mutant, and in platelets from JAK2 V617F knock-in mice that were treated in vivo with JAK2 or proteasome inhibitors. In addition, we show that Tpo can induce both proliferative and antiproliferative effects via TpoR at low and high JAK2 activation levels, respectively, or on expression of JAK2 V617F. The antiproliferative signaling and receptor down-modulation by JAK2 V617F were dependent on signaling via TpoR cytosolic tyrosine 626. We propose that selection against TpoR antiproliferative signaling occurs by TpoR down-modulation and that restoration of down-modulated TpoR levels could become a biomarker for the treatment of MPNs. (Blood. 2012; 119(20):4625-4635)
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available