Abstract Solid‐state NMR spectroscopy is being used to determine the structures of membrane proteins involved in the regulation of apoptosis and ion transport. The Bcl‐2 family includes pro‐ and anti‐apoptotic proteins that play a major regulatory role in mitochondrion‐dependent apoptosis or programmed cell death. The NMR data obtained for 15 N‐labeled anti‐apoptotic Bcl‐xL in lipid bilayers are consistent with membrane association through insertion of the two central hydrophobic α‐helices that are also required for channel formation and cytoprotective activity. The FXYD family proteins regulate ion flux across membranes, through interaction with the Na + , K + ‐ATPase, in tissues that perform fluid and solute transport or that are electrically excitable. We have expressed and purified three FXYD family members, Mat8 (mammary tumor protein), CHIF (channel‐inducing factor) and PLM (phospholemman), for structure determination by NMR in lipids. The solid‐state NMR spectra of Bcl‐2 and FXYD proteins, in uniaxially oriented lipid bilayers, give the first view of their membrane‐associated architectures. Copyright © 2004 John Wiley & Sons, Ltd.