Clathrin adaptor proteins, also known as adaptins, are proteins that mediate the formation of vesicles for intracellular trafficking and secretion.
Adaptins are clustered subunits of adaptor protein (AP) complexes.
[1] There are several types of adaptin, each related to a different AP complex.
Adaptins show sequence similarity to some COPI subunits, thus they are thought to have a common evolutionary origin.
[1] The adaptin is a heterotetramer consisting of two large adaptins (beta and one other depending on the complex), a medium adaptin (mu), and a small adaptin (sigma): A diagram of the 5 complexes is shown here This membrane protein–related article is a stub.