Figure 2.

Latrunculin B abrogates the insulin response but only slightly reduces the hypertonic response of GLUT4myc translocation to the plasma membrane. L6-GLUT4myc myoblasts were serum starved for 3 h and pretreated with 1 μM latrunculin B for 1 h, followed by the addition of 100 nM insulin or 0.45 M hypertonic sucrose for 30 min only as indicated. Intact cells were labeled with anti-myc IgG. Cell surface GLUT4myc was determined by measuring bound HRP-conjugated secondary antibody by using the enzyme-linked o-phenylenediamine dihydrochloride detection assay, by following the optical absorbance at 492 nm. Background o-phenylenediamine dihydrochloride absorbance (measured by secondary antibody labeling only) was subtracted from all values. Data are shown as fold increase over basal ± SE for each experimental condition; p < 0.01 relative to basal (^*) control.