RIPA buffer is one of the most useful protein extraction buffers and maintains most native structures of proteins. Nevertheless, RIPA buffer is not convenient enough to extract membrane proteins and membrane-associated proteins concentrated in lipid raft.
Lipid raft is a highly unique microdomain on the lipid bilayer which contains special lipids, cholesterol and functional proteins. In this layer, lipid raft-enriched proteins are usually insoluble in mild detergent buffers such as 1% Triton X-100 and RIPA buffer. Consequently, it was, up to now, difficult to analyze the functions of this kind of proteins.
