The JAK-STAT pathway is a crucial signaling mechanism in cells that helps transmit information from outside the cell to the nucleus. It involves two main types of proteins: Janus kinases (JAKs) and signal transducers and activators of transcription (STATs). When a signaling molecule, like a cytokine, binds to its receptor on the cell surface, JAKs are activated and phosphorylate STATs, leading to their activation. Once activated, the STATs dimerize and translocate to the nucleus, where they regulate the expression of specific genes. This pathway plays a vital role in various biological processes, including immune response, cell growth, and differentiation. Dysregulation of the JAK-STAT pathway can contribute to diseases such as cancer and autoimmune disorders.