Fig. 3.

Cdk5 activity and NF-H tail domain phosphorylation are inhibited by anti-α₁β₁ functional blocking antibodies and cdk5 inhibitor BL-1 in RA-treated SH-SY5Y cells grown on laminin. A, Cell lysates were prepared from RA-treated SH-SY5Y cells cultured on laminin in the presence of anti-β₁ (DE9) and anti-α₁ (FB12) in the absence of antibodies or treated with the cdk5 inhibitor BL-1 (10 μm) or PD98059, a specific MEK inhibitor (50 μm), for 24 hr. Immunoprecipitates obtained with cdk5 antibody were assayed for their ability to phosphorylate histone H1.B, Both total NF-H and phospho-NF-H tail domain were detected in cell lysates as described in A by Western blot analysis using anti-NF-H C-terminal phospho-independent antibody SMI33 for total NF-H (bottom panel) and monoclonal phospho-specific antibody SMI31 for phosphorylated NF-H KSP tail domain (top panel). Equal amounts of protein were loaded in each lane. PL, Poly-l-lysine;LN, laminin.