Fluorescence deconvolution micrograph showing the transcription factor NF-kB (nuclear factor kappa-light-chain-enhancer of activated B cells, red) in heart muscle tissue from an adult. The actin of the muscle's contractile fibres is shown in green and the blue areas are cell nuclei. NF-kB is a protein complex associated with cell death processes and plays a key role in regulating the immune response to infection.