Chinese hamster ovary cell lysosomes retain pinocytized horseradish peroxidase and in situ-radioiodinated proteins

Journal Article · Wed Feb 01 04:00:00 EST 1984 · Mol. Cell. Biol.; (United States)

DOI:https://doi.org/10.1128/MCB.4.2.296· OSTI ID:6851526

Storrie, B; Sachdeva, M; Viers, V S

We used Chinese hamster ovary cells, a cell line of fibroblastic origin, to investigate whether lysosomes are an exocytic compartment. To label lysosomal contents, Chinese hamster ovary cells were incubated with the solute marker horseradish peroxidase. After an 18-h uptake period, horseradish peroxidase was found in lysosomes by cell fractionation in Percoll gradients and by electron microscope cytochemistry. Over a 24-h period, lysosomal horseradish peroxidase was quantitatively retained by Chinese hamster ovary cells and inactivated with a t 1/2 of 6 to 8 h. Lysosomes were radioiodinated in situ by soluble lactoperoxidase internalized over an 18-h uptake period. About 70% of the radioiodine incorporation was pelleted at 100,000 X g under conditions in which greater than 80% of the lysosomal marker enzyme beta-hexosaminidase was released into the supernatant. By one-dimensional electrophoresis, about 18 protein species were present in the lysosomal membrane fraction, with radioiodine incorporation being most pronounced into species of 70,000 to 75,000 daltons. After a 30-min or 2-h chase at 37 degrees C, radioiodine that was incorporated into lysosomal membranes and contents was retained in lysosomes. These observations indicate that lysosomes labeled by fluid-phase pinocytosis are a terminal component of endocytic pathways in fibroblasts.

• Research Organization: Department of Biochemistry and Nutrition, Virginia Polytechnic Institute and State University, Blacksburg
• OSTI ID: 6851526
• Journal Information: Mol. Cell. Biol.; (United States), Journal Name: Mol. Cell. Biol.; (United States) Vol. 4:2; ISSN MCEBD
• Country of Publication: United States
• Language: English

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550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMAL CELLS
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CHEMICAL REACTIONS
CHO CELLS
ENZYMES
HALOGENATION
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
IODINATION
IODINE ISOTOPES
ISOTOPES
LABELLING
LYSOSOMES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANOIDS
OXIDOREDUCTASES
PEROXIDASES
PORPHYRINS
RETENTION