This gene encodes a membrane protein that is a member of a class of protein-tyrosine kinases (PTK) characterized by the presence of a second phosphotransferase-related domain immediately N-terminal to the PTK domain. The encoded kinase phosphorylates STAT proteins (signal transducers and activators of transcription) and plays a key role in interferon-alpha/beta and interferon-gamma signal transduction. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Mar 2016],JAK1A, JAK1B, JTK3,Apoptosis,Apoptosis_Inhibition of Apoptosis,Cancer,Cell Biology & Developmental Biology,Cytokines,Epigenetics & Nuclear Signaling,ErbB-HER Signaling Pathway,IL-6 Receptor Signaling Pathway,Immunology & Inflammation,Kinase,Kinase_Tyrosine kinases,PI3K-Akt Signaling Pathway,Protein phosphorylation,Signal Transduction,JAK1