Targeting of lysosomal enzymes via the mannose-6-phosphate receptor: 1) transfer of N-acetylglucosamine-1-phosphate to mannose via phosphotransferase (defective in ML-II and ML-III), 2) removal of N-acetylglucosamine exposing the mannose-6-phosphate marker, 3) recognition and binding of lysosomal enzymes to the mannose-6-phosphate receptor, 4) transport of lysosomal enzymes to lysosomes, 5) recycling of mannose-6-phosphate receptors back to the Golgi membrane, 6) abnormal secretion of lysosomal enzymes that fail to acquire the mannose-6-phosphate marker, as in ML-II and ML-III. Source: Lysosomal Disorders, Pediatric Endocrinology and Inborn Errors of Metabolism, 2e Citation: Sarafoglou K, Hoffmann GF, Roth KS. Pediatric Endocrinology and Inborn Errors of Metabolism, 2e; 2017 Available at: http://accesspediatrics.mhmedical.com/DownloadImage.aspx?image=/data/books/2042/saraped2_ch45_f010.png&sec=154117735&BookID=2042&ChapterSecID=154117568&imagename= Accessed: November 13, 2017 Copyright © 2017 McGraw-Hill Education. All rights reserved