Fig. 5

Spontaneous induction of caveolins and cavins by proximal tubule epithelial cell dissociation and culture. a. Immunohistochemical staining for caveolin-1/CAV1 in a manually isolated proximal tubule. Caveolin-1/CAV1 is positive in most cells growing out from the collapsed proximal tubule. b. Proximal tubules were manually isolated to homogeneity, enzymatically dissociated and cultured. Following formalin fixation, cells were stained for caveolin-1/CAV1. Only a minor fraction of colonies should have been positive for caveolin-1/CAV1 if cultures were overgrown by a caveolin-1/CAV1- positive progenitor cell, but instead we found all resulting colonies to be positive. The increased expression of caveolins (CAV1–3) and cavins (PTRF/CAVIN1, SDPR/CAVIN2 and PRKCDBP/CAVIN3) with time in culture are illustrated by Western blot in panel (c). Panel d presents the increased expression of caveolin-1/CAV1 when cultured in serum free medium (SFM). Quantification of Western blot data is shown in Additional file 3: Figure S3