CD95 is a death receptor that can promote oncogenesis through molecular mechanisms that are not fully elucidated. Although the mature CD95 membrane receptor is considered to start with the arginine at position 17 after elimination of the signal peptide, this receptor can also be cleaved by MMP7 upstream of its leucine at position 37. This post-translational modification occurs in cancer cells but also in normal cells such as peripheral blood leukocytes. The non-cleaved CD95 amino-terminal region consists in a disordered domain and its in silico reconstitution suggests that it might contribute to receptor aggregation and thereby, regulate the downstream death signaling pathways. In agreement with this molecular modeling analysis, the comparison of CD95-deficient cells reconstituted with full-length or N-terminally truncated CD95 reveals that the loss of the amino-terminal region of CD95 impairs the initial steps of the apoptotic signal while favoring the induction of pro-survival signals, including the PI3K and MAPK pathways.
© 2022. The Author(s).

The basis of traditional flow cytometry allergy diagnosis is measurement of the expression of basophilic surface activation and/or degranulation markers. Basophils, upon encounter with a specific allergen that cross-links surface FcRI-bound IgE antibodies, not only secrete and release quantifiable bioactive mediators but also upregulate the expression of different markers (e.g., CD63, CD203c) which can be detected by multicolor flow cytometry using specific monoclonal antibodies. Here, we describe a novel technique that relies upon the staining of exteriorized anionic proteoglycans from a basophil granule matrix by cationic fluorescent avidin probes.

Basophils and mast cells (MCs) are important effector cells in the immune system. For a long time, it has been known that these cells can be activated though the cross-linking of IgE antibodies bound to their high-affinity receptor (FcεRI). However, evidence has accumulated suggesting that these cells can also be activated by various IgE-independent mechanisms. Occupation of MAS Related GPR Family Member X2 (MRGPRX2), a G protein-coupled receptor, is described as an alternative IgE-independent activation mechanism. Here we describe a flow cytometric technique to analyze MRGPRX2 expression and its functionality on cultured human MCs and conditioned basophils, that is, basophils with upregulated surface expression of MRGPRX2.