背景资料：WD repeat and FYVE domain-containing protein 2 (WDFY2), also known as WDF2 and ZFYVE22, is a 400 amino acid protein that localizes to a set of small endosomes that are found within 100 nm from the plasma membrane. Highly conserved between species, WDFY2 consists of one FYVE-type zinc finger and seven WD repeats. The FYVE domain is a cysteine-rich domain of about 70 amino acids. Its primary role is to target signal-transducing proteins to cell membranes through binding to the membrane lipid phosphatidylinositol-3-phosphate with high specificity. WD-repeats are generally found in clusters of seven. They have no intrinsic catalytic activity, but they serve as a platform for protein-protein interactions. WDFY2 is suspected to play a critical role in the endocytic pathway.