CD32A was cross-linked on neutrophil membranes as described in the Materials and methods section. Membranes were then solubilized for 20 min in 1% NP40 on ice, 1% NP40 at 37 °C or 100 mM OGD on ice. After centrifugation (15000 g, 10 min), the supernatants (S) and pellets (P) were analysed by SDS/PAGE and probed for CD32A, Hck, Lyn or Fgr as described in the Materials and methods section. M, whole membranes before solubilization in detergents.