Quantitative Proteome Analysis of Mouse Liver Lysosomes Provides Evidence for Mannose 6-phosphate-independent Targeting Mechanisms of Acid Hydrolases in Mucolipidosis II

TY - JOUR

T1 - Quantitative Proteome Analysis of Mouse Liver Lysosomes Provides Evidence for Mannose 6-phosphate-independent Targeting Mechanisms of Acid Hydrolases in Mucolipidosis II

AU - Markmann, Sandra

AU - Krambeck, Svenja

AU - Hughes, Christopher J

AU - Mirzaian, Mina

AU - Aerts, Johannes M F G

AU - Saftig, Paul

AU - Schweizer, Michaela

AU - Vissers, Johannes P C

AU - Braulke, Thomas

AU - Damme, Markus

N1 - © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

PY - 2017/3

Y1 - 2017/3

N2 - The efficient receptor-mediated targeting of soluble lysosomal proteins to lysosomes requires the modification with mannose 6-phosphate (M6P) residues. Although the absence of M6P results in misrouting and hypersecretion of lysosomal enzymes in many cells, normal levels of lysosomal enzymes have been reported in liver of patients lacking the M6P-generating phosphotransferase (PT). The identity of lysosomal proteins depending on M6P has not yet been comprehensively analyzed. In this study we purified lysosomes from liver of PT-defective mice and 67 known soluble lysosomal proteins were identified that illustrated quantitative changes using an ion mobility-assisted data-independent label-free LC-MS approach. After validation of various differentially expressed lysosomal components by Western blotting and enzyme activity assays, the data revealed a small number of lysosomal proteins depending on M6P, including neuraminidase 1, cathepsin F, Npc2, and cathepsin L, whereas the majority reach lysosomes by alternative pathways. These data were compared with findings on cultured hepatocytes and liver sinusoid endothelial cells isolated from the liver of wild-type and PT-defective mice. Our findings show that the relative expression, targeting efficiency and lysosomal localization of lysosomal proteins tested in cultured hepatic cells resemble their proportion in isolated liver lysosomes. Hypersecretion of newly synthesized nonphosphorylated lysosomal proteins suggest that secretion-recapture mechanisms contribute to maintain major lysosomal functions in liver.

AB - The efficient receptor-mediated targeting of soluble lysosomal proteins to lysosomes requires the modification with mannose 6-phosphate (M6P) residues. Although the absence of M6P results in misrouting and hypersecretion of lysosomal enzymes in many cells, normal levels of lysosomal enzymes have been reported in liver of patients lacking the M6P-generating phosphotransferase (PT). The identity of lysosomal proteins depending on M6P has not yet been comprehensively analyzed. In this study we purified lysosomes from liver of PT-defective mice and 67 known soluble lysosomal proteins were identified that illustrated quantitative changes using an ion mobility-assisted data-independent label-free LC-MS approach. After validation of various differentially expressed lysosomal components by Western blotting and enzyme activity assays, the data revealed a small number of lysosomal proteins depending on M6P, including neuraminidase 1, cathepsin F, Npc2, and cathepsin L, whereas the majority reach lysosomes by alternative pathways. These data were compared with findings on cultured hepatocytes and liver sinusoid endothelial cells isolated from the liver of wild-type and PT-defective mice. Our findings show that the relative expression, targeting efficiency and lysosomal localization of lysosomal proteins tested in cultured hepatic cells resemble their proportion in isolated liver lysosomes. Hypersecretion of newly synthesized nonphosphorylated lysosomal proteins suggest that secretion-recapture mechanisms contribute to maintain major lysosomal functions in liver.

KW - Animals

KW - Cells, Cultured

KW - Chromatography, Liquid

KW - Disease Models, Animal

KW - Gene Expression Regulation

KW - Hydrolases

KW - Liver

KW - Lysosomes

KW - Mannosephosphates

KW - Mass Spectrometry

KW - Mice

KW - Mucolipidoses

KW - Phosphotransferases

KW - Proteome

KW - Journal Article

U2 - 10.1074/mcp.M116.063636

DO - 10.1074/mcp.M116.063636

M3 - SCORING: Journal article

C2 - 28062798

VL - 16

SP - 438

EP - 450

JO - MOL CELL PROTEOMICS

JF - MOL CELL PROTEOMICS

SN - 1535-9476

IS - 3

ER -