May act as a scaffolding protein within caveolar membranes, functionally participating in formation of caveolae or caveolae-like vesicles. Heterooligomeric complex of flotillin-1 and flotillin-2 and caveolin-1 and caveolin-2. Interacts with ECPAS (By similarity). Identified by mass spectrometry in melanosome fractions from stage I to stage IV (By similarity). Membrane-associated protein of caveola (PubMed:9153235). High expression in brain, white adipose tissue, heart muscle, skeletal muscle and lung. Low expression in spleen, liver and testis. Expression increases at least 10-fold as 3T3-L1 cells differentiate into adipocytes. Belongs to the band 7/mec-2 family. Flotillin subfamily.