Fluid phase endocytosis and galactosyl receptor-mediated endocytosis employ different early endosomes

Hyperosmolarity inhibits galactosyl receptor-mediated but not fluid phase endocytosis in isolated rat hepatocytes.

We have investigated the effects of hyperosmolarity induced by sucrose on the fluid phase endocytosis of the fluorescent dye lucifer yellow CH (LY) and the endocytosis of 125I-asialo-orosomucoid (ASOR) by the galactosyl receptor system in isolated rat hepatocytes. Continuous uptake of LY by cells at 37 degrees C is biphasic, occurs for 3-4 h, and then plateaus. Permeabilized cells or crude memb...

Endosomes and Golgi vesicles in adsorptive and fluid phase endocytosis

We studied with morphometric methods the endocytosis by pheochromocytoma cells of a conjugate of wheat germ agglutinin with ferritin (WGA-Ft) and of horseradish peroxidase (HRP). Quantitative studies indicated that WGA-Ft was cleared slowly from cell surfaces and that it was not recycled to the surface. Cells labeled with WGA-Ft for 15 min at room temperature were washed and incubated in medium...

Receptor-mediated endocytosis.

Receptor - mediated endocytosis

In 1934, Lewis described the process ofpinocytosis an invagination of the plasma membrane enclosing a small droplet of fluid. Pinocytosis appeared to be a constitutive process, whereas phagocytosis described some years earlier by Metchnikoffwas regulated. Only within the last two decades has it been recognized that (i) during pinocytosis cells internalize vast amounts of membrane. indeed, more ...

Receptor-mediated endocytosis of asialoglycoproteins by rat hepatocytes: receptor-positive and receptor-negative endosomes

We have used combinations of subcellular fractionation, specific cytochemical tracers, and quantitative immunoadsorption to determine when, where, and in which intracellular structure internalized asialoglycoproteins (ASGPs) are segregated from their receptor. All membrane vesicles containing the receptor (R+ vesicles) were quantitatively immunoadsorbed from crude microsomes with Staphylococcus...