Fig 4.

Overexpression of β4-WT and β4-MUT induces neurite extension and increases the formation of filopodia-like protrusions in Neuro2a cells. (A, B) Overexpression of β4-WT and β4-MUT in Neuro2a cells displayed a marked alteration in cell morphology. High-magnification images of Neuro2a cells overexpressing vector, β4-WT and β4-MUT immunostained by anti-β4 (red) and GFP⁺ (green) are shown. Scale bar 30 μm for A; Scale bar 5 μm for B. (C) The quantification of the average neurite extension induced by β4-WT and β4-MUT. The average neurite length for cells overexpressing β4-WT and β4-MUT were significantly greater than those for the vector control transfected cells (**p < 0.01); the average neurite length for the β4-MUT overexpressing cells were higher than the β4-WT transfected cells (*p < 0.05). (D) The quantification of the number of filopodia-like protrusions. The cells overexpressing β4-WT and β4-MUT had a significantly increased number of filopodia-like protrusions (*p < 0.05, **p < 0.01). The number of filopodia-like protrusions in the β4-MUT transfected cells was significantly higher than the β4-WT cells (*p < 0.05). The values in the histograms are means ± SEM.