Reference Detail

Contact

Missing content? – Request curation!

Request curation for specific Genes, Variants, or PubMed publications.

Have questions, comments, or suggestions? - Let us know!

Email us at : ckbsupport@jax.org

Ref Type Journal Article
PMID (26668133)
Authors Chachoua I, Pecquet C, El-Khoury M, Nivarthi H, Albu RI, Marty C, Gryshkova V, Defour JP, Vertenoeil G, Ngo A, Koay A, Raslova H, Courtoy PJ, Choong ML, Plo I, Vainchenker W, Kralovics R, Constantinescu SN
Title Thrombopoietin receptor activation by myeloproliferative neoplasm associated calreticulin mutants.
URL
Abstract Text Mutations in the calreticulin gene (CALR) represented by deletions and insertions in exon 9 inducing a -1/+2 frameshift are associated with a significant fraction of myeloproliferative neoplasms (MPNs). The mechanisms by which CALR mutants induce MPN are unknown. Here, we show by transcriptional, proliferation, biochemical, and primary cell assays that the pathogenic CALR mutants specifically activate the thrombopoietin receptor (TpoR/MPL). No activation is detected with a battery of type I and II cytokine receptors, except granulocyte colony-stimulating factor receptor, which supported only transient and weak activation. CALR mutants induce ligand-independent activation of JAK2/STAT/phosphatydylinositol-3'-kinase (PI3-K) and mitogen-activated protein (MAP) kinase pathways via TpoR, and autonomous growth in Ba/F3 cells. In these transformed cells, no synergy is observed between JAK2 and PI3-K inhibitors in inhibiting cytokine-independent proliferation, thus showing a major difference from JAK2V617F cells where such synergy is strong. TpoR activation was dependent on its extracellular domain and its N-glycosylation, especially at N117. The glycan binding site and the novel C-terminal tail of the mutant CALR proteins were required for TpoR activation. A soluble form of TpoR was able to prevent activation of full-length TpoR provided that it was N-glycosylated. By confocal microscopy and subcellular fractionation, CALR mutants exhibit different intracellular localization from that of wild-type CALR. Finally, knocking down either MPL/TpoR or JAK2 in megakaryocytic progenitors from patients carrying CALR mutations inhibited cytokine-independent megakaryocytic colony formation. Taken together, our study provides a novel signaling paradigm, whereby a mutated chaperone constitutively activates cytokine receptor signaling.

Filtering

  • Case insensitive filtering will display rows if any text in any cell matches the filter term
  • Use simple literal full or partial string matches
  • Separate multiple filter terms with a space. Any order may be used (i. e. a b c and c b a are equivalent )
  • Filtering will only apply to rows that are already loaded on the page. Filtering has no impact on query parameters.
  • Use quotes to match on a longer phrase with spaces (i.e. "mtor c1483f")

Sorting

  • Generally, the default sort order for tables is set to be first column ascending; however, specific tables may set a different default sort order.
  • Click on any column header arrows to sort by that column
  • Hold down the Shift key and click multiple columns to sort by more than one column. Be sure to set ascending or descending order for a given column before moving on to the next column.

Molecular Profile Treatment Approach
Gene Name Source Synonyms Protein Domains Gene Description Gene Role
Therapy Name Drugs Efficacy Evidence Clinical Trials
Drug Name Trade Name Synonyms Drug Classes Drug Description
Gene Variant Impact Protein Effect Variant Description Associated with drug Resistance
Molecular Profile Indication/Tumor Type Response Type Therapy Name Approval Status Evidence Type Efficacy Evidence References