![Fig. 1. MLCK activation during PMNL phagocytosis. / (A) Kinase activity. PMNLs (2 × 106/mL) were challenged with EIgG (1 × 108/mL) (circles) or incubated with no EIgG (triangles) at 37°C for the indicated times. PMNL lysates were prepared by probe sonication as described in “Materials and methods.” MLCK was assayed in the lysates by phosphorylation of substrate peptide (myosin light chain, amino acids 11-23) in the presence of [γ-32P]ATP for 10 minutes at 30°C. Data represent the mean ± SEM of 4 experiments. Significantly different from time 0 sample; P < .05. (B) Phosphorylation of endogenous myosin light chain. PMNLs were labeled with 32P, challenged with EIgG (P) or not stimulated (U) for 4 minutes, and lysed. Samples were immunoprecipitated with antiplatelet myosin and subjected to 12% SDS-PAGE followed by autoradiography.](https://ash.silverchair-cdn.com/ash/content_public/journal/blood/95/7/10.1182_blood.v95.7.2407/5/bloo00702001ax.jpeg?Expires=1722418139&Signature=G-Rsb4wft7BPqQp-fMIfjXpJhSelP3uBVA55SKGcRV7XwEiLKKNAKCk61M8VxnlGMxKbO950qmMbQOnrIsJXoLGlHkrh0m8rzN8FuY~7mh0UxmqrqDIPisCwV-XBC8Ej8Q1V7tNLBRZkGYstfeD-cy~-9eoNszmD7H7XtHlEDSAa-8OAF01DOskqbjQaAzTIBfjpNA~x1mnLgJhZw-xy0qSTItnSwGMVu03Sbza6PLrJee3P7O4WasV7d0PfyLF3G~vDMjnHrTbomT5qbvDp-YdhrL5vfwS2hVeTf~fD~S81c-a2puKB6kgLVSEOKdNNCI8G1TVzotT3v1RKxGNA9w__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA)
MLCK activation during PMNL phagocytosis.
(A) Kinase activity. PMNLs (2 × 106/mL) were challenged with EIgG (1 × 108/mL) (circles) or incubated with no EIgG (triangles) at 37°C for the indicated times. PMNL lysates were prepared by probe sonication as described in “Materials and methods.” MLCK was assayed in the lysates by phosphorylation of substrate peptide (myosin light chain, amino acids 11-23) in the presence of [γ-32P]ATP for 10 minutes at 30°C. Data represent the mean ± SEM of 4 experiments. Significantly different from time 0 sample; P < .05. (B) Phosphorylation of endogenous myosin light chain. PMNLs were labeled with 32P, challenged with EIgG (P) or not stimulated (U) for 4 minutes, and lysed. Samples were immunoprecipitated with antiplatelet myosin and subjected to 12% SDS-PAGE followed by autoradiography.
