Preparation of detergent-resistant membranes (DRMs) from cultured mammalian cells

Detergent-resistant membranes (DRMs) isolated from cells are enriched in proteins and lipids with a high affinity for lipid rafts, or membrane microdomains in the liquid-ordered phase. Enrichment in DRMs provides a good indication that a protein is "raftophilic," and may be present in rafts in cell membranes before extraction. Here, I describe preparation of Triton X-100-insoluble DRMs from cultured mammalian cells on sucrose gradients. Methods for analyzing the distribution of particular proteins across the gradient, and for recovering DRMs for further use are presented.