Fig. 7.

A model of L1 trafficking in the axonal growth cone migrating via an L1-dependent mechanism. L1 is internalized from the plasma membrane at the C-domain via clathrin-mediated pathways. Subsequently, endocytosed L1 is transported into the P-domain via sorting and recycling endosomes, a process that is dependent on the dynamic ends of microtubules (not shown in this figure). Then, trafficking L1 is reinserted into the plasma membrane at the leading edge. Recycled L1 on the cell surface moves toward the C-domain most likely by coupling to the retrogradely moving actin filaments via ankyrin or other linker molecules. The L1CD has at least two different states depending on conformation or phosphorylation. L1's interaction with ankyrin is regulated by phosphorylation (Garver et al., 1997), as is its ability to interact with clathrin adaptors (see last paragraph of Discussion for details).