JAKSTATsignalvägen

JAKSTATsignalvägen refers to the signaling pathway involving Janus kinases (JAKs) and Signal Transducers and Activators of Transcription (STATs). This pathway is a critical component of cellular communication, playing a vital role in regulating gene expression in response to a wide range of extracellular signals. These signals typically include cytokines, growth factors, and hormones.

The JAK-STAT pathway begins when a ligand, such as a cytokine, binds to its specific receptor on the cell surface. This binding event causes receptor dimerization, which in turn brings associated JAK proteins into close proximity. The JAKs then phosphorylate each other, activating their kinase activity. Activated JAKs subsequently phosphorylate tyrosine residues on the intracellular domains of the receptor.

These phosphorylated tyrosine residues serve as docking sites for STAT proteins. STATs, which are latent transcription factors, are recruited to the receptor complex and are then phosphorylated by the activated JAKs on a specific tyrosine residue. This phosphorylation event induces STAT dimerization. Dimerized STATs then translocate to the nucleus, where they bind to specific DNA sequences (GAS elements) in the promoter regions of target genes. This binding initiates or represses the transcription of these genes, thereby mediating the cellular response to the initial signal. The JAK-STAT pathway is involved in diverse cellular processes including cell growth, differentiation, survival, and immune responses. Dysregulation of this pathway has been implicated in various diseases, including cancer and inflammatory disorders.