Protein expression is the process by which proteins are synthesized in a cell, typically through the transcription and translation of genes. This research area focuses on understanding the mechanisms responsible for regulating protein expression, as well as the factors that influence protein levels in cells. Protein expression studies are important for determining the functions of individual proteins, elucidating their roles in biological processes, and identifying potential targets for drug development. Researchers use a variety of techniques, such as western blotting, immunohistochemistry, and mass spectrometry, to study protein expression levels in different cell types and under various conditions.