Abstract
Cytokines and growth factors are signaling molecules that regulate a variety of biological processes. Understanding their role is essential for basic research and clinical utilization. Thus, cytokines and growth factors are widely used throughout research labs in a significant number of applications. Additionally, genetic polymorphisms result in variant forms of cytokines and growth factors, which can alter their function. Becoming more common, researchers will need to generate these important proteins and their variants themselves in functional forms for activity studies. The expression systems used to generate these proteins can have a major impact on their function. In some instances, post-translational modifications are needed to produce a functionally active protein, which can only be conducted using eukaryotic expression systems. Ideally, for functional relevance, a human expression system should be used for human-related research and applications. Most human cell-based expression systems primarily use HEK (Human Embryonic Kidney) cells; however, relying on just one cell type can lead to several issues, considering the variety of proteins derived from various cell sources. Here, we provide a protocol to effectively and efficiently generate functional recombinant proteins, taking into consideration the diverse range of proteins from different cell types throughout the human body.