(A) Lysosomes from mouse fibroblasts transfected with wild‐type hLAMP‐2A and maintained in the presence (Serum+) or absence (serum−) of serum were collected by centrifugation and subjected to Triton X‐114 extraction, sucrose density gradient centrifugation and immunobloting for human (hL2A) or mouse (mL2A) LAMP‐2A. Lane 1: homogenate. 