| Structural highlights
Disease
STXB2_HUMAN Familial hemophagocytic lymphohistiocytosis. The disease is caused by mutations affecting the gene represented in this entry.
Function
STXB2_HUMAN Involved in intracellular vesicle trafficking and vesicle fusion with membranes. Contributes to the granule exocytosis machinery through interaction with soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins that regulate membrane fusion. Regulates cytotoxic granule exocytosis in natural killer (NK) cells.[1] [2]
Publication Abstract from PubMed
Mutations in either syntaxin 11 (Stx11) or Munc18-2 abolish cytotoxic T lymphocytes (CTL) and natural killer cell (NK) cytotoxicity, and give rise to familial hemophagocytic lymphohistiocytosis (FHL4 or FHL5, respectively). Although Munc18-2 is known to interact with Stx11, little is known about the molecular mechanisms governing the specificity of this interaction or how in vitro IL-2 activation leads to compensation of CTL and NK cytotoxicity. To understand how mutations in Munc18-2 give rise to disease, we have solved the structure of human Munc18-2 at 2.6 A resolution and mapped 18 point mutations. The four surface mutations identified (R39P, L130S, E132A, P334L) map exclusively to the predicted syntaxin and soluble N-ethylmaleimide-sensitive factor accessory protein receptor binding sites of Munc18-2. We find that Munc18-2 binds the N-terminal peptide of Stx11 with a approximately 20-fold higher affinity than Stx3, suggesting a potential role in selective binding. Upon IL-2 activation, levels of Stx3 are increased, favoring Munc18-2 binding when Stx11 is absent. Similarly, Munc18-1, expressed in IL-2-activated CTL, is capable of binding Stx11. These findings provide potential explanations for restoration of Munc18-Stx function and cytotoxicity in IL-2-activated cells.
Syntaxin binding mechanism and disease-causing mutations in Munc18-2.,Hackmann Y, Graham SC, Ehl S, Honing S, Lehmberg K, Arico M, Owen DJ, Griffiths GM Proc Natl Acad Sci U S A. 2013 Nov 5. PMID:24194549[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ zur Stadt U, Rohr J, Seifert W, Koch F, Grieve S, Pagel J, Strauss J, Kasper B, Nurnberg G, Becker C, Maul-Pavicic A, Beutel K, Janka G, Griffiths G, Ehl S, Hennies HC. Familial hemophagocytic lymphohistiocytosis type 5 (FHL-5) is caused by mutations in Munc18-2 and impaired binding to syntaxin 11. Am J Hum Genet. 2009 Oct;85(4):482-92. doi: 10.1016/j.ajhg.2009.09.005. PMID:19804848 doi:http://dx.doi.org/10.1016/j.ajhg.2009.09.005
- ↑ Cote M, Menager MM, Burgess A, Mahlaoui N, Picard C, Schaffner C, Al-Manjomi F, Al-Harbi M, Alangari A, Le Deist F, Gennery AR, Prince N, Cariou A, Nitschke P, Blank U, El-Ghazali G, Menasche G, Latour S, Fischer A, de Saint Basile G. Munc18-2 deficiency causes familial hemophagocytic lymphohistiocytosis type 5 and impairs cytotoxic granule exocytosis in patient NK cells. J Clin Invest. 2009 Dec;119(12):3765-73. doi: 10.1172/JCI40732. Epub 2009 Nov 2. PMID:19884660 doi:http://dx.doi.org/10.1172/JCI40732
- ↑ Hackmann Y, Graham SC, Ehl S, Honing S, Lehmberg K, Arico M, Owen DJ, Griffiths GM. Syntaxin binding mechanism and disease-causing mutations in Munc18-2. Proc Natl Acad Sci U S A. 2013 Nov 5. PMID:24194549 doi:http://dx.doi.org/10.1073/pnas.1313474110
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