Cell Biology

Phagosome Proteome

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Science  12 Jan 2001:
Vol. 291, Issue 5502, pp. 211
DOI: 10.1126/science.291.5502.211d

The biochemical characterization of intracellular compartments has a long and respected history. The goal is to define each of the components of an organelle, and to understand how it gets there and what its function in the organelle is.

Garin et al. have combined traditional subcellular fractionation techniques with modern proteomics technology to provide a detailed analysis of the constituents of the phagosome, an organelle created by cells when they engulf and digest particles, such as bacteria, from the extracellular milieu. Macrophages were fed latex beads, which permitted a straightforward purification by flotation of phagosomes away from other organelles of the endocytic and secretory pathways. The purified phagosomes contained over 140 proteins, including degradative enzymes, the vacuolar proton pump, and membrane fusion machinery. The degradative enzymes appeared to be acquired sequentially during phagosome maturation. In addition, a surprising number of apoptosis (or programmed cell death)-related proteins also were found in the phagosomes, indicating an unanticipated role for the phagosome in assessing a cell's state of health. — SMH

J. Cell Biol.152, 165 (2001)

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