Are caveolae involved in clathrin-independent endocytosis?

In addition to endocytosing molecules via clathrin-coated pits, cells also internalize membrane and fluid by a clathrin-independent endocytic mechanism. In this article we search for the equivalent of clathrin-coated pits in clathrin-independent endocytosis, and discuss some pitfalls in the interpretation of electron micrographs. We also discuss how the early steps in clathrin-independent endocytosis might be analysed morphologically, and we argue that caveolae are not involved in clathrin-independent endocytosis.