LIMP-2 is a receptor for lysosomal mannose-6-phosphate-independent targeting of beta-glucocerebrosidase.
beta-glucocerebrosidase, the enzyme defective in Gaucher disease, is targeted to the lysosome independently of the mannose-6-phosphate receptor. Affinity-chromatography experiments revealed that the lysosomal integral membrane protein LIMP-2 is a specific binding partner of beta-glucocerebrosidase. This interaction involves a coiled-coil domain within the lumenal domain. beta-glucocerebrosidase activity and protein levels were severely decreased in LIMP-2-deficient mouse tissues. Analysis of fibroblasts and macrophages isolated from these mice indicated that the majority of beta-glucocerebrosidase was secreted. Missorting of beta-glucocerebrosidase was also evident in vivo, as protein and activity levels were significantly higher in sera from LIMP-2-deficient mice compared to wild-type. Reconstitution of LIMP-2 in LIMP-2-deficient fibroblasts led to a rescue of beta-glucocerebrosidase levels and distribution. LIMP-2 expression also led to lysosomal transport of a beta-glucocerebrosidase endoplasmic reticulum retention mutant. These data support a role for LIMP-2 as the mannose-6-phosphate-independent trafficking receptor for beta-glucocerebrosidase.
Reczek
David
D
Genzyme Corporation, 1 Mountain Road, Framingham, MA 01701, USA. david.reczek@genzyme.com
Schwake
Michael
M
Schröder
Jenny
J
Hughes
Heather
H
Blanz
Judith
J
Jin
Xiaoying
X
Brondyk
William
W
Van Patten
Scott
S
Edmunds
Tim
T
Saftig
Paul
P
D000595:Amino Acid Sequence; D000818:Animals; D018955:CD36 Antigens / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D004721:Endoplasmic Reticulum / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D005776:Gaucher Disease / Q000378:metabolism*; D005962:Glucosylceramidase / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D051907:Lysosomal Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008247:Lysosomes / Q000378:metabolism*; D008264:Macrophages / Q000166:cytology / Q000378:metabolism; D008360:Mannosephosphates / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D011485:Protein Binding; D017433:Protein Structure, Secondary; D021381:Protein Transport; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment
D018955:CD36 Antigens; D051907:Lysosomal Membrane Proteins; D008360:Mannosephosphates; D011994:Recombinant Proteins; C489452:Scarb2 protein, mouse; C027693:mannose-6-phosphate; D005962:Glucosylceramidase