這個基因編碼酪氨酸激酶的一個成員，更具體地說，是janus激酶（jaks）蛋白家族。該蛋白與I型和II型細胞因子受體的胞質結構域相關，并通過磷酸化受體亞單位釋放細胞因子信號。它也是I型和III型干擾素信號通路的組成部分。因此，它可能在抗病毒免疫中發揮作用。該基因突變與高免疫球蛋白e綜合征（hies）有關，hies是一種以血清免疫球蛋白e升高為特征的原發性免疫缺陷。
This gene encodes a member of the tyrosine kinase and, more specifically, the Janus kinases (JAKs) protein families. This protein associates with the cytoplasmic domain of type I and type II cytokine receptors and promulgate cytokine signals by phosphorylating receptor subunits. It is also component of both the type I and type III interferon signaling pathways. As such, it may play a role in anti-viral immunity. A mutation in this gene has been associated with hyperimmunoglobulin E syndrome (HIES) - a primary immunodeficiency characterized by elevated serum immunoglobulin E. [provided by RefSeq, Jul 2008]