IL7RA associates with JAK1 Authored: Ray, KP, 2010-05-17 Edited: Jupe, S, 2011-05-06 IL7RA has the small juxta-membrane "Box1" motif, conserved throughout the type I cytokine receptor family (Murakami et al. 1991). This is believed to be the site of JAK1 binding (Tanner et al. 1995); deletion of Box1 eliminates JAK1 phosphorylation (Jiang et al. 2004). Studies with T-cell lines expressing mutant IL-4/IL-7 chimeric receptors revealed that loss of Box1 results in rapid cell death, while Y449F mutation causes cell cycle arrest that precedes cell death (Jiang et al. 2004). Mice expressing a knock-in mutation (IL-7R alpha Y449F) displayed defective homeostatic proliferation of naive CD4 and CD8 T-cells (Osbourne et al. 2007). The Y449 site is thus of particular interest because two critical IL-7 signaling pathways, the JAK/STAT pathway and the phosphatidylinositol 3-kinase (PI3K)/AKT pathway may originate from this site (Pallard et al. 1999). Pubmed10367898 Pubmed15226449 Pubmed15996891 Pubmed1662392 Pubmed17325202 Pubmed7896787 Pubmed9287175 Reactome Database ID Release 431264832 Reactome, http://www.reactome.org ReactomeREACT_116023 Reviewed: Puck, J, 2011-11-03 IL7RA:JAK1