(C) Intact ratliverlysosomes (top) and DR regions of the lysosomal membranes (bottom) were fixed and subjected to immunogold labeling for LAMP‐2A and LAMP‐2B, and a gold‐conjugated secondary antibody as described under Material and methods. Top right panels show 'clusters' of gold particles (black arrows) in individual lysosomes at higher magnification. Graph shows the labeling density (gold particles per μm) in the indicated fractions for both proteins. Values are mean+s.e. from the quantification of 15 different micrographs. 