Interaction of NUMB with L1

Numb is thought to be a phosphotyrosine binding (PTB) domain containing cargo specific adaptor protein, which links specific cargo to the endocytic machinery. It associates with collapsin response mediator protein-2 (CRMP 2) with its PTB domain and alpha adaptin (a subunit of the AP 2 adaptor complex) through its tripeptide Asp-Pro-Phe (DPF) motif, and is involved in clathrin dependent endocytosis at the plasma membrane. Numb is associated with L1 under physiological conditions and functions in endocytosis of L1 in the C domain membrane of axonal growth cones.

Numb被认为是一种含有磷酸酪氨酸结合（PTB）结构域的货物特异性适配蛋白，该蛋白将特定货物与内吞作用机器连接起来。Numb通过其PTB结构域与胶原反应介导蛋白-2（CRMP 2）及其三肽Asp-Pro-Phe（DPF）基序与α适配蛋白（AP 2适配复合体亚基）相联系，并在质膜上参与依赖网格蛋白的内吞作用。在生理条件下，Numb与L1结合，并在轴突生长锥的C域膜上介导L1的内吞作用。