Component of the adaptor complexes which link clathrin to receptors in coated vesicles (Probable). Clathrin-associated protein complexes are believed to interact with the cytoplasmic tails of membrane proteins, leading to their selection and concentration (Probable). Required for many aspects of development and behavior, including negative regulation of vulval differentiation. Required for the dendritic localization of potassium channel kvs-4 in the cholinergic motor neuron DA9