β1-integrin plays an instructive role in MAG-induced growth cone turning. A-C. Growth cone turning in the presence of uniform activation by MAG. Shown are sample images of growth cone turning of P5 rat hippocampal neuron axons in a gradient of Ha2/5 (0.5 mg/ml in the pipette, A) or saline (B) with uniform presence of MAG (150 ng/ml) in the bath. Scale bar: 20 μm. Also shown is the summary of growth cone turning angles under different conditions, C). Values represent mean ± s.e.m. Numbers associated with the bar graph indicate the number of growth cones analyzed. "*" indicates significant difference (p < 0.01, ANOVA). D. MAG-induced growth cone turning in the present of uniform activation of β1-integrin. Same as in (C), except that neurons were subjected to a MAG gradient (150 μg/ml in the pipette) with uniform presence of the β1-intergin activating peptide YIGSR (10 μg/ml), or the control peptide LKVAV (10 μg/ml), respectively.