Role of Slp3 in SG degranulation. (A) BMMCs were electroporated with siRNAs targeting Slp3 (n°1 or n°2) or with control siRNA. Transfected BMMCs were lysed and analyzed by Western blotting using anti-Slp3 and antitubulin as a loading control. (B) Control or Slp3 siRNA n°1 or Slp3 siRNA n°2 was cotransfected with GFP alone. GFP⁺ BMMCs were then assessed for CD63 expression using flow cytometry (left), and expression was quantified (ΔMFI CD63⁺; right). (C, left) BMMCs were electroporated with siRNAs targeting Slp3 (n°1 or n°2) or with control siRNA, along with GFP. IgE-sensitized electroporated BMMCs were either not stimulated, or were stimulated with 20 ng/ml DNP-HSA for 10 min. Cells were fixed, permeabilized, and stained with anti-STX3 antibody. Bars, 2 µm. (Right) In each individual experiment in the nonstimulated condition (n = 2), stimulated condition for 10 min (n = 2), and stimulated condition for 30 min (n = 2), >30 cells distributed in different areas of the glass coverslip were counted. Statistical analyses were performed using unpaired t tests. **, P < 0.005; ***, P < 0.0001. MFI, mean fluorescence intensity.