Figure 4.

Effects on MLCK activity and eosinophil locomotion of variants of MLCK inhibitory peptide LSM1. (A) Amino acid sequences of LSM1 and variants containing glutamate (E) and caged tyrosine (cgY). (B) Effects of LSM1 peptides on constitutively active catalytic domain of MLCK before (•) and after (○) photoconversion; the photoreleased peptide was indistinguishable from authentic LSM1 in inhibitory potency, chromatographic behavior and mass spectra. Loss of inhibitory potency for 9E-LSM1 (▵) illustrates the requirement for Y in position 9 for inhibitory activity. Data represent means of triplicate measurements with SEM values less than 10% of the mean. (C–J) Effects of photorelease of LSM1 on eosinophil locomotion. Phase contrast images of an eosinophil injected with 9cgY-LSM1, before (C and D), during (E), and after (F–H) near-UV exposure with times in sec. Color coded outlines of the same cell at the designated intervals before (I) and after (J) photorelease of LSM1.