PTPμ expression and catalytic activity is required for neurite outgrowth on N-cadherin and E-cadherin. E8 chick retinal explants were infected with HSV encoding GFP control (A, E, I), PTPμ WT (B, F, J), PTPμ AS (C, G, K) or PTPμ C–S (D, H, L) and cultured on laminin (A, B, C, D), N-cadherin (E, F, G, H) or E-cadherin (I, J, K,L) substrates for 20 hours. No difference in neurite length or density was observed in cultures infected with GFP, PTPμ WT, PTPμ AS, or PTPμ C–S when cultured on laminin (A, B, C, D). Overexpression of PTPμ WT also had no effect on laminin (B), N-cadherin (F) or E-cadherin (J) substrates. Infection with PTPμ AS or PTPμ C–S resulted in a dramatic decrease in neurite outgrowth when cultured on N-cadherin (G, H) or E-cadherin (K, L) substrates. Scale bar, 200 μm.