Cation-dependent mannose 6-phosphate receptor contains two internalization signals in its cytoplasmic domain [published erratum appears in Proc Natl Acad Sci U S A 1991 Feb 15;88(4):1591] The signals required for rapid internalization of the bovine cation-dependent mannose 6-phosphate receptor have been localized to two distinct regions of the 67-amino acid cytoplasmic domain. One signal includes phenylalanine 13 and phenylalanine 18, while the other involves tyrosine 45. The former signal is more potent than the latter, but both must be present for the maximal rate of receptor internalization. Each signal shares similarities with the known internalization signals of other recycling receptors. 