scholarly journals Role of LAMP-2 in Lysosome Biogenesis and Autophagy

2002 ◽  
Vol 13 (9) ◽  
pp. 3355-3368 ◽  
Author(s):  
Eeva-Liisa Eskelinen ◽  
Anna Lena Illert ◽  
Yoshitaka Tanaka ◽  
Günter Schwarzmann ◽  
Judith Blanz ◽  
...  
Keyword(s):  
Half Life ◽  
Lysosomal Enzymes ◽  
State Level ◽  
Autophagic Vacuoles ◽  
Lysosome Biogenesis ◽  
Golgi Region ◽  
Activity Measurements ◽  
Phenotype Analysis ◽  
Mannose 6 Phosphate

In LAMP-2–deficient mice autophagic vacuoles accumulate in many tissues, including liver, pancreas, muscle, and heart. Here we extend the phenotype analysis using cultured hepatocytes. In LAMP-2–deficient hepatocytes the half-life of both early and late autophagic vacuoles was prolonged as evaluated by quantitative electron microscopy. However, an endocytic tracer reached the autophagic vacuoles, indicating delivery of endo/lysosomal constituents to autophagic vacuoles. Enzyme activity measurements showed that the trafficking of some lysosomal enzymes to lysosomes was impaired. Immunoprecipitation of metabolically labeled cathepsin D indicated reduced intracellular retention and processing in the knockout cells. The steady-state level of 300-kDa mannose 6-phosphate receptor was slightly lower in LAMP-2–deficient hepatocytes, whereas that of 46-kDa mannose 6-phosphate receptor was decreased to 30% of controls due to a shorter half-life. Less receptor was found in the Golgi region and in vesicles and tubules surrounding multivesicular endosomes, suggesting impaired recycling from endosomes to the Golgi. More receptor was found in autophagic vacuoles, which may explain its shorter half-life. Our data indicate that in hepatocytes LAMP-2 deficiency either directly or indirectly leads to impaired recycling of 46-kDa mannose 6-phosphate receptors and partial mistargeting of a subset of lysosomal enzymes. Autophagic vacuoles may accumulate due to impaired capacity for lysosomal degradation.

scholarly journals Disturbed Cholesterol Traffic but Normal Proteolytic Function in LAMP-1/LAMP-2 Double-deficient Fibroblasts

2004 ◽  
Vol 15 (7) ◽  
pp. 3132-3145 ◽  
Author(s):  
Eeva-Liisa Eskelinen ◽  
Christine Katrin Schmidt ◽  
Silja Neu ◽  
Marion Willenborg ◽  
Graciela Fuertes ◽  
...  
Keyword(s):  
Fibroblast Cell ◽  
Cholesterol Homeostasis ◽  
Receptor Expression ◽  
Autophagic Vacuoles ◽  
Lysosome Biogenesis ◽  
Degradation Rates ◽  
Percoll Gradients ◽  
Chaperone Mediated Autophagy ◽  
Fibroblast Cell Lines

Mice double deficient in LAMP-1 and -2 were generated. The embryos died between embryonic days 14.5 and 16.5. An accumulation of autophagic vacuoles was detected in many tissues including endothelial cells and Schwann cells. Fibroblast cell lines derived from the double-deficient embryos accumulated autophagic vacuoles and the autophagy protein LC3II after amino acid starvation. Lysosomal vesicles were larger and more peripherally distributed and showed a lower specific density in Percoll gradients in double deficient when compared with control cells. Lysosomal enzyme activities, cathepsin D processing and mannose-6-phosphate receptor expression levels were not affected by the deficiency of both LAMPs. Surprisingly, LAMP-1 and -2 deficiencies did not affect long-lived protein degradation rates, including proteolysis due to chaperone-mediated autophagy. The LAMP-1/2 double-deficient cells and, to a lesser extent, LAMP-2 single-deficient cells showed an accumulation of unesterified cholesterol in endo/lysosomal, rab7, and NPC1 positive compartments as well as reduced amounts of lipid droplets. The cholesterol accumulation in LAMP-1/2 double-deficient cells could be rescued by overexpression of murine LAMP-2a, but not by LAMP-1, highlighting the more prominent role of LAMP-2. Taken together these findings indicate partially overlapping functions for LAMP-1 and -2 in lysosome biogenesis, autophagy, and cholesterol homeostasis.

scholarly journals In exocrine pancreas, the basolateral endocytic pathway converges with the autophagic pathway immediately after the early endosome.

1990 ◽  
Vol 111 (2) ◽  
pp. 329-345 ◽  
Author(s):  
J Tooze ◽  
M Hollinshead ◽  
T Ludwig ◽  
K Howell ◽  
B Hoflack ◽  
...  
Keyword(s):  
Acid Phosphatase ◽  
Lysosomal Enzymes ◽  
Early Endosome ◽  
Endocytic Pathway ◽  
Cell Periphery ◽  
Type I ◽  
Type Ii ◽  
Autophagic Vacuoles ◽  
Early Endosomes ◽  
Mannose 6 Phosphate

Intracisternal granules (ICGs) are insoluble aggregates of pancreatic digestive enzymes and proenzymes that develop within the lumen of the rough endoplasmic reticulum of exocrine pancreatic cells, especially in guinea pigs. These ICGs are eliminated by autophagy. By morphological criteria, we identified three distinct and sequential classes of autophagic compartments, which we refer to as phagophores, Type I autophagic vacuoles, and Type II autophagic vacuoles. Lobules of guinea pig pancreas were incubated in media containing HRP for periods of 5-120 min to determine the relationship between the endocytic and autophagic pathways. Incubations with HRP of 15 min or less labeled early endosomes at the cell periphery that were not involved in autophagy of ICGs, but after these short incubations none of the autophagic compartments were HRP positive. After 30-min incubation with HRP, early endosomes at the cell periphery, late endosomes in the pericentriolar region, and, in addition, Type I autophagic vacuoles containing ICGs were all labeled by the tracer. Type II autophagic vacuoles were not labeled after 30-min incubation with HRP but were labeled after incubations of 60-120 min. Phagophores did not receive HRP even after 120 min incubations. We concluded that the autophagic and endocytic pathways converge immediately after the early endosome level and that Type I autophagic vacuoles precede Type II autophagic vacuoles on the endocytic pathway. We studied the distribution of acid phosphatase, lysosomal proteases and cation-independent-mannose-6-phosphate receptor (CI-M6PR) in the three classes of autophagic compartments by histochemical and immunocytochemical methods. Phagophores, the earliest autophagic compartment, contained none of these markers. Type I autophagic vacuoles contained acid phosphatase but, at most, only very low levels of cathepsin D and CI-M6PR. Type II autophagic vacuoles, by contrast, are enriched for acid phosphatase, cathepsin D, and other lysosomal enzymes, and they are also enriched for CI-M6PR. Moreover, soluble fragments of bovine CI-M6PR conjugated to colloidal gold particles heavily labeled Type II but not Type I autophagic vacuoles, and this labeling was specifically blocked by mannose-6-phosphate. This indicates that the lysosomal enzymes present in Type II autophagic vacuoles carry mannose-6-phosphate monoester residues. Using 3-C2, 4-dinitroanilino-3'-amino-N-methyldipropylamine (DAMP), we showed that Type II autophagic vacuoles are acidic. We interpret these findings as indicating that Type II autophagic vacuoles are a prelysosomal compartment in which the already combined endocytic and autophagic pathways meet the delivery pathway of lysosomal enzymes.

Endocytosis of Sugars in Embryonic Skeletal Tissues in Organ Culture

1969 ◽  
Vol 4 (1) ◽  
pp. 139-154
Author(s):  
J. T. DINGLE ◽  
HONOR B. FELL ◽  
AUDREY M. GLAUERT
Keyword(s):  
Organ Culture ◽  
Lysosomal Enzymes ◽  
Articular Chondrocytes ◽  
Appreciable Amount ◽  
Neutral Salt ◽  
Normal Medium ◽  
Limb Bone ◽  
Cytoplasmic Vacuolation ◽  
Golgi Region

Cultivation of limb-bone rudiments in medium containing various non-metabolizable or poorly metabolizable sugars caused vacuolation of the perichondrial and articular cells and was accompanied by an increased synthesis and profuse secretion of lysosomal enzymes. Experiments with [14C] dextran indicated that the cytoplasmic vacuolation was due not to a higher rate of endocytosis, but rather to an abnormally long persistence of the pinocytotic vacuoles. Metachromatic material was lost from the cartilage only in the immediate vicinity of the vacuolated articular chondrocytes and the amount of hexosamine and hydroxyproline released into the medium was not much increased. However, the hexosamine and hydroxyproline of the sucrose treated rudiments was much more susceptible to extraction with neutral salt than those of paired controls. Sucrose taken up by the cells was liberated when the rudiments were returned to normal medium; this release, unlike the secretion of lysosomal enzymes, was unaffected by the presence of hydrocortisone. It is probable that the primary lysosornes, formed in the enlarged Golgi region, are the vehicles for the secretion of lysosomal enzymes. No appreciable amount of enzyrnic activity was released into the medium from rudiments grown in the presence of 0.08 M sucrose, before 36 h; at, or just before this time, however, a net increase in synthesis of enzyme was observed. The role of endocytosis in the resorption of skeletal matrix is discussed.

THE ROLE OF LYSOSOMAL ENZYMES IN THE PATHOGENESIS OF SHOCK. 2, THE ORIGIN OF PLASMA LYSOSOMAL HYDROLASES IN SHOCK

1979 ◽  
Vol 29 (1) ◽  
pp. 33-38
Author(s):  
RYO OGAWA ◽  
TAKASUKE IMAI ◽  
TATSUSHI FUJITA
Keyword(s):  
Lysosomal Enzymes ◽  
Lysosomal Hydrolases

The Role of Archpriest Eugene Popov in Enhancing of the Anglican-Orthodox Dialog

2020 ◽  
pp. 71-84
Author(s):  
Ярослав Очканов
Keyword(s):  
State Level ◽  
Structural Features ◽  
Russian Orthodox ◽  
Church Community ◽  
Anglican Church ◽  
Current State ◽  
The Church

Статья посвящена исследованию малоизученной стороны деятельности видного русского священнослужителя протоиерея Евгения Попова, бывшего с 1842 по 1875 гг. настоятелем русской посольской церкви в Лондоне. Его служение на Английской земле совпало с углублением диалога между Русской Православной и Англиканской церквами, явившегося следствием религиозных преобразований в Англии в 1830 - 1840-е гг. Отец Евгений в рассматриваемый период фактически стал связующим звеном между русским церковноначалием и англиканами - инициаторами единения двух Церквей. Он проделал огромную работу по популяризации православия в Англии и много сделал для ознакомления русской церковной общественности с вероучением и структурными особенностями англиканства. Материалом для исследования послужили, прежде всего, письма протоиерея Евгения Попова обер-прокурорам Святейшего Синода Н. А. Протасову и А. П. Толстому. Эти документы являются своеобразными отчётами о современном состоянии Англиканской Церкви, о религиозных течениях в ней и усилиях, предпринимаемых определёнными церковными кругами в Англии по сближению с православием. Результаты его деятельности имели важное значение в последующие десятилетия, когда англикано-православный диалог вышел на церковно-государственный уровень. The article is devoted to the insufficiently studied aspects of Russian prominent cleric Archpriest Eugene Popov, rector of Russian Embassy Church in London from 1842 to 1875. His Ministry on the English soil coincided with the deepening of the dialogue between the Russian Orthodox and Anglican Churches, which was the result of religious transformations in England in the 1830s and 1840s. Father Eugene in the period under consideration actually became a connecting link between the Russian Church authorities and the anglicans-initiators of the union of the two Churches. He had done a great job by popularizing Orthodoxy in England and by familiarizing the Russian Church community with the doctrine and structural features of Anglicanism. The study, first of all, is based the letters of Archpriest Yevgeny Popov to the chief prosecutors of the Holy Synod N. A. Protasov and A. P. Tolstoy, which were original reports on the current state of the Anglican Church, it’s religious trends, and the efforts made by certain Church circles in England to get closer to Orthodoxy. The fruits of his activities were important in the following decades, when the Anglican-Orthodox dialogue reached the Church-state level.

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