Mutant RBL mast cells defective in Fc epsilon RI signaling and lipid raft biosynthesis are reconstituted by activated Rho-family GTPases.

ABSTRACT: Characterization of defects in a variant subline of RBL mast cells has revealed a biochemical event proximal to IgE receptor (Fc epsilon RI)-stimulated tyrosine phosphorylation that is required for multiple functional responses. This cell line, designated B6A4C1, is deficient in both Fc epsilon RI-mediated degranulation and biosynthesis of several lipid raft components. Agents that bypass receptor-mediated Ca(2+) influx stimulate strong degranulation responses in these variant cells. Cross-linking of IgE-Fc epsilon RI on these cells stimulates robust tyrosine phosphorylation but fails to mobilize a sustained Ca(2+) response. Fc epsilon RI-mediated inositol phosphate production is not detectable in these cells, and failure of adenosine receptors to mobilize Ca(2+) suggests a general deficie

SUBMITTER: Field KA 

PROVIDER: S-EPMC15022 | biostudies-literature | 2000 Oct

REPOSITORIES: biostudies-literature