The **JAK-STAT signaling pathway** is a chain of interactions between proteins in a cell, and is involved in processes such as [immunity](https://en.wikipedia.org/wiki/Immunity_(medical) "Immunity (medical)"), [cell division](https://en.wikipedia.org/wiki/Cell_growth "Cell growth"), [cell death](https://en.wikipedia.org/wiki/Apoptosis "Apoptosis"), and [tumour formation](https://en.wikipedia.org/wiki/Oncogenesis "Oncogenesis"). The pathway communicates information from chemical signals outside of a cell to the [cell nucleus](https://en.wikipedia.org/wiki/Cell_nucleus "Cell nucleus"), resulting in the activation of genes through the process of [transcription](https://en.wikipedia.org/wiki/Transcription_(biology) "Transcription (biology)"). There are three key parts of JAK-STAT signalling: [Janus kinases](https://en.wikipedia.org/wiki/Janus_kinase "Janus kinase") (JAKs), [signal transducer and activator of transcription proteins](https://en.wikipedia.org/wiki/STAT_protein "STAT protein") (STATs), and receptors (which bind the chemical signals). Disrupted JAK-STAT signalling may lead to a variety of diseases, such as skin conditions, [cancers](https://en.wikipedia.org/wiki/Cancer "Cancer"), and disorders affecting the immune system.