TY - JOUR

T1 - uPARAP/endo180 directs lysosomal delivery and degradation of collagen IV

AU - Kjøller, Lars

AU - Engelholm, Lars H

AU - Høyer-Hansen, Maria

AU - Danø, Keld

AU - Bugge, Thomas H.

AU - Behrendt, Niels

PY - 2004/2/1

Y1 - 2004/2/1

N2 - Collagen turnover is crucial for tissue homeostasis and remodeling and pathological processes such as cancer invasion, but the underlying molecular mechanisms are poorly understood. A major pathway appears to be internalization and degradation by fibroblasts. We now show that the endocytic transmembrane glycoprotein urokinase plasminogen activator receptor-associated protein (uPARAP/endo180) directs collagen IV for lysosomal delivery and degradation. In wild-type fibroblasts, fluorescently labeled collagen IV was first internalized into vesicular structures with diffuse fluorescence eventually appearing uniformly within the wild-type cells after longer incubation times. In these cells, some collagen-containing vesicles were identified as lysosomes by staining for LAMP-1. In contrast, collagen IV remained extracellular and associated with fiber-like structures on uPARAP/endo180-deficient fibroblasts. Blocking lysosomal cysteine proteases with the inhibitor E64d resulted in strong accumulation of collagen IV in lysosomes in wild-type cells, but only very weak intracellular fluorescence accumulation in uPARAP/endo180-deficient fibroblasts. We conclude that uPARAP/endo180 is critical for targeted delivery of collagen IV to lysosomes for degradation implicating the receptor in normal and malignant extracellular matrix degradation. A similar localization pattern was observed for collagen V, suggesting that uPARAP/endo180 might be generally involved in collagen degradation.

AB - Collagen turnover is crucial for tissue homeostasis and remodeling and pathological processes such as cancer invasion, but the underlying molecular mechanisms are poorly understood. A major pathway appears to be internalization and degradation by fibroblasts. We now show that the endocytic transmembrane glycoprotein urokinase plasminogen activator receptor-associated protein (uPARAP/endo180) directs collagen IV for lysosomal delivery and degradation. In wild-type fibroblasts, fluorescently labeled collagen IV was first internalized into vesicular structures with diffuse fluorescence eventually appearing uniformly within the wild-type cells after longer incubation times. In these cells, some collagen-containing vesicles were identified as lysosomes by staining for LAMP-1. In contrast, collagen IV remained extracellular and associated with fiber-like structures on uPARAP/endo180-deficient fibroblasts. Blocking lysosomal cysteine proteases with the inhibitor E64d resulted in strong accumulation of collagen IV in lysosomes in wild-type cells, but only very weak intracellular fluorescence accumulation in uPARAP/endo180-deficient fibroblasts. We conclude that uPARAP/endo180 is critical for targeted delivery of collagen IV to lysosomes for degradation implicating the receptor in normal and malignant extracellular matrix degradation. A similar localization pattern was observed for collagen V, suggesting that uPARAP/endo180 might be generally involved in collagen degradation.

KW - Animals

KW - Animals, Newborn

KW - Antibodies, Monoclonal

KW - Antigens, CD

KW - Cells, Cultured

KW - Collagen Type IV

KW - Cysteine Endopeptidases

KW - Enzyme Inhibitors

KW - Fibroblasts

KW - Kinetics

KW - Leucine

KW - Lysosome-Associated Membrane Glycoproteins

KW - Lysosomes

KW - Membrane Glycoproteins

KW - Mice

KW - Mice, Knockout

KW - Rats

KW - Receptors, Cell Surface

KW - Skin

KW - Subcellular Fractions

KW - Comparative Study

KW - Journal Article

KW - Research Support, Non-U.S. Gov't

M3 - Journal article

C2 - 14729061

VL - 293

SP - 106

EP - 116

JO - Experimental Cell Research

JF - Experimental Cell Research

SN - 0014-4827

IS - 1

ER -