Clathrin is axonally transported as part of slow component b: the microfilament complex.

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Abstract
During axonall transport, membranes travel down axons at a rapid rate, whereas the cytoskeletal elements travel in either of 2 slow components, SC[slow component]a (with tubulin and neurofilament protein) and SCb (with actin). Clathrin, the highly ordered, structural coat protein of coated vesicles, was recently shown to interact in vitro with cytoskeletal proteins in addition to membranes. Whether clathrin travels preferentially with the membrane elements or the cytoskeletal elements when it is axonally transported was studied. Guinea pig visual system was labeled with tritiated amino acids. Radioactive SDS[sodium dodecyl sulfate]-polyacrylamide gel electrophoresis profiles from the major components of transport were coelectrophoresed with clathrin. Only SCb had a band comigrating with clathrin. Radioactive clathrin was purified from guinea pig brain containing only radioactive SCb polypeptides. Kinetic analysis of the putative clathrin band in SCb revealed that it travels entirely within the SCb wave. Apparently, clathrin travels preferentially with the cytoskeletal proteins making up SCb, rather than with the membranes and membrane-associated proteins in the fast component.