Plasma Membrane Vesiculation: A New Technique for Isolation of Plasma Membranes

TLDR

The study proposes a novel method to isolate plasma membrane vesicles from cultured cells. The method isolates vesicles by treating monolayer cultures of macrophages, monocytes, myoblasts, and fibroblasts with formaldehyde, related low‑molecular‑weight aldehydes, and disulfide‑blocking agents, yielding vesicles enriched in cholesterol, sphingomyelin, and 5′‑nucleotidase activity. The resulting vesicles have a unique protein and lipid composition, a seven‑to‑tenfold enrichment of 5′‑nucleotidase activity, trilamellar membranes, and no ultrastructural evidence of contamination with other cytoplasmic organelles.

Abstract

Monolayer cell cultures of macrophages, monocytes, myoblasts, and density-inhibited and transformed fibroblasts form and release cell surface membrane vesicles following exposure to formaldehyde, related low-molecular-weight aldehydes, and disulfide blocking agents. Vesicles have a unique composition of proteins and lipids. They show enrichment of cholesterol and sphingomyelin content and a seven-to tenfold enrichment of 5′-nucleotidase activity. Vesicles also contain intramembranous particles and show a trilamellar unit membrane and no ultrastructural evidence of contamination with other cytoplasmic organelles. The technique is proposed as a novel method for isolating plasma membrane vesicles from cells in culture.