Fig. 4. (A) Cell adhesion to various matrix proteins. Cell attachment was measured using adhesion strips coated with various extracellular matrix proteins. Attached cells were stained with crystal violet, and total adhesion was quantified by measuring absorbance at 540 nm. (B) The effect of Cdk5 overexpression on cell adhesion to a fibronectin matrix. Cell attachment to fibronectin-coated cell adhesion strips was measured for cells that were stably transfected with Cdk5 or a dominant-negative construct, Cdk5T33. Attached cells were stained with crystal violet and total adhesion was quantified by measuring absorbance at 540 nm.