Syt VII is a Ca(2+) sensor that regulates lysosome exocytosis and plasma membrane repair. Because it lacks motifs that mediate lysosomal targeting, it is unclear how Syt VII traffics to these organelles. In this paper, we show that mutations or inhibitors that abolish palmitoylation disrupt Syt VII targeting to lysosomes, causing its retention in the Golgi complex. In macrophages, Syt VII is tr...

Methods 83 subjects (66/17 females/males) with reported food adverse reactions were included in the study. Eighteen atopic/allergic subjects were included as controls for the foods to which they had reported no reactions. BAT was performed on heparinazed blood incubated with food extracts. CD63 activation marker was evaluated on basophils by flow-cytometry. The stimulation index (SI) was calcul...

Human papillomaviruses enter host cells via a clathrin-independent endocytic pathway involving tetraspanin proteins. However, post-endocytic trafficking required for virus capsid disassembly remains unclear. Here we demonstrate that the early trafficking pathway of internalised HPV particles involves tetraspanin CD63, syntenin-1 and ESCRT-associated adaptor protein ALIX. Following internalisati...

In macrophages, lysosomes are suspected to have a heterogenous population of vesicles. This study was thus undertaken to identify and to characterize lysosomal compartments in human macrophages. Hck is a Src-family tyrosine kinase associated with secretory lysosomes in neutrophils and with cytoplasmic vesicles in macrophages that fuse with phagosomes. We identified these Hck-positive vesicles a...

Although fluoroquinolones (FQs) are generally well-tolerated antibiotics, increasing numbers of hypersensitivity reactions have been reported. These can be evaluated in vitro by basophil activation tests (BATs); however, sensitivity is not optimal. Many factors could influence sensitivity such as basophil activation markers. The objective of this study was to evaluate the influence of 2 differe...

BACKGROUND The basophil activation test (BAT), in which translocation of markers to the surface of blood basophils is measured in response to allergen by flow cytometry, is a rapid assay that is gaining popularity. Two markers are currently being evaluated for the BAT; CD63 and the lineage-specific CD203c. In a recent report, detection of CD203c after lysis with Saponin was shown to be superior...

CD63 is a lysosomal membrane protein that belongs to the tetraspanin family. Its carboxyterminal cytoplasmic tail sequence contains the lysosomal targeting motif GYEVM. Strong, tyrosine-dependent interaction of the wild-type carboxyterminal tail of CD63 with the AP-3 adaptor subunit mu 3 was observed using a yeast two-hybrid system. The strength of interaction of mutated tail sequences with mu ...