Discusses research being done on the importance of a phospholipid, phosphatidylinositol-4,5-biphosphate in endocytosis. Reference to the studies by T. Itoh et al and M.G.J. Ford et al published in the February 9, 2001 issue of "Science"; Proteins involved in endocytosis that contain an epsin amino-terminal homology (ENTH) domain; Difference of the amino terminus of clathrin assembly lymphoid-myeloid leukemia with the ENTH of epsin.