title: Extending the mannose 6-phosphate glycoproteome by high resolution/accuracy mass spectrometry analysis of control and acid phosphatase 5-deficient mice.
abstract: In mammals, most newly synthesized lumenal lysosomal proteins are delivered to the lysosome by the mannose 6-phosphate (Man6P) targeting pathway. Man6P -containing proteins can be affinity-purified and characterized using proteomic approaches, and such studies have led to the discovery of new lysosomal proteins and associated human disease genes. One limitation to this approach is that in most cell types the Man6P modification is rapidly removed by acid phosphatase 5 (ACP5) after proteins are targeted to the lysosome, and thus, some lysosomal proteins may escape detection. In this study, we have extended the analysis of the lysosomal proteome using high resolution/accuracy mass spectrometry to identify and quantify proteins in a combined analysis of control and ACP5-deficient mice. To identify Man6P glycoproteins with limited tissue distribution, we analyzed multiple tissues and used statistical approaches to identify proteins that are purified with high specificity. In addition to 68 known Man6P glycoproteins, 165 other murine proteins were identified that may contain Man6P and may thus represent novel lysosomal residents. For four of these lysosomal candidates, (lactoperoxidase, phospholipase D family member 3, ribonuclease 6, and serum amyloid P component), we demonstrate lysosomal residence based on the colocalization of fluorescent fusion proteins with a lysosomal marker.
authors.affiliation: Center for Advanced Biotechnology and Medicine, Piscataway, New Jersey 08854, USA. sleat@cabm.rutgers.edu
authors.forename: David E
authors.initials: DE
authors.lastname: Sleat
authors.forename: Pengling
authors.initials: P
authors.lastname: Sun
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Wiseman
authors.forename: Ling
authors.initials: L
authors.lastname: Huang
authors.forename: Mukarram
authors.initials: M
authors.lastname: El-Banna
authors.forename: Haiyan
authors.initials: H
authors.lastname: Zheng
authors.forename: Dirk F
authors.initials: DF
authors.lastname: Moore
authors.forename: Peter
authors.initials: P
authors.lastname: Lobel
mesh_terms: D000135:Acid Phosphatase / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism*; D008247:Lysosomes / Q000378:metabolism*; D008360:Mannosephosphates / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D020543:Proteome; D053719:Tandem Mass Spectrometry / Q000379:methods; D000071681:Tartrate-Resistant Acid Phosphatase
chemical_list: D007527:Isoenzymes; D008360:Mannosephosphates; D020543:Proteome; C027693:mannose-6-phosphate; C000605510:ACP5 protein, human; D000135:Acid Phosphatase; C000605511:Acp5 protein, mouse; D000071681:Tartrate-Resistant Acid Phosphatase