Figure 6
Mutations of Ser988 in the α4 cytoplasmic domain that mimic phosphorylation reduce paxillin binding and inhibit α4-mediated neurite outgrowth. A) Lysates of biotin-labelled PC12 cells expressing the different α4 constructs immunoprecipitated with anti-α4 antibody as in Fig 1 and visualised by streptavidin peroxidase/ECL (upper panel) or by western blotting with anti-paxillin antibody (lower panel). Note that the phospho-mimicking S988D mutation prevents paxillin binding and co-immunoprecipitation. B) Neurite outgrowth of PC12 cells expressing the different α4 constructs and mock-transfected PC12 cells measured as in Fig. 1. The data shown are the mean ± SEM of 3 experiments. Note that the S988D mutation also inhibits α4-mediated neurite outgrowth (* = P < 0.01).