Caveolae
In biology, caveolae (from Latin little cave) are small invaginations of the plasma membrane in many cell types, especially in endothelian[?] cells. Some cell types, like neurons, completely lack caveolae.
These flask-shaped structures rich of proteins and lipids and are used for several functions in signal transduction (Anderson, 1998 (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9759488&dopt=Abstract)). They are also discussed to play a role in endocytosis, oncogenesis[?], and the uptake of pathogenic bacteria.
The formation and maintenance of caveolae is primarily due to the protein caveolin[?].