Subcellular fractionation of tissue culture cells

Development of cell fractionation techniques over the last few decades has provided the means to analyze the composition and properties of purified cellular elements. In particular, subcellular fractionation is essential for the development of cell-free assays that reconstitute complicated cellular processes. These assays have provided new and important tools to understand the molecular mechanisms of complex cellular functions, permitting these functions to be studied in the test tube as a series of biochemical reactions. The protocols in this unit describe fractionation of tissue culture cells to immunoisolate early and late endosomes under conditions where these compartments retain their capacity to support membrane transport in vitro.