The distribution of AP-3 proteins and trafficking of LAMP-1 in cno/cno fibroblasts.

The distribution of AP-3 proteins and trafficking of LAMP-1 are normal in cno/cno fibroblasts. (A-F) Immunofluorescence staining of fibroblasts derived from wild-type C3H/HeJ (wt; panels A and D), mocha (mh; panels B and E) and cappuccino (cno; panels C and F) mice, with the use of antibodies to the δ (panels A-C) and β3A (panels D-F) subunits of the AP-3 complex. Note the characteristic punctate pattern of AP-3 in the cytoplasm of wt andcno/cno fibroblasts and its apparent absence frommh/mh fibroblasts. (G-I) Fluorescence microscopy detection of anti–LAMP-1 monoclonal antibody internalized by wt (panel G),mh/mh (panel H) and cno/cno (panel I) fibroblasts for 15 minutes at 37°C. Bar, 20 μm. (J) Quantitation of antibody internalization experiments. The amounts of internalized antibody in samples, prepared as in panels G through I, were estimated by image analysis of 5 randomly selected fields, as described.26Background-corrected values are expressed in arbitrary units of fluorescence per cell (mean ± SD of the number of experiments indicated in parentheses). *P < .01.