Journal article Open Access
Russell, S.; Johnston, J.; Noguchi, M.; Kawamura, M.; Bacon, C.; Friedmann, M.; Berg, M.; McVicar, D.; Witthuhn, B.; Silvennoinen, O.; Et, A.-L.
Interleukin-2 (IL-2) signaling requires the dimerization of the IL-2 receptor beta.(IL-2R beta) and common gamma (gamma c) chains. Mutations of gamma c can result in X-linked severe combined immunodeficiency (XSCID). IL-2, IL-4, IL-7 (whose receptors are known to contain gamma c), and IL-9 (whose receptor is shown here to contain gamma c) induced the tyrosine phosphorylation and activation of the Janus family tyrosine kinases Jak1 and Jak3. Jak1 and Jak3 associated with IL-2R beta and gamma c, respectively; IL-2 induced Jak3-IL-2R beta and increased Jak3-gamma c associations. Truncations of gamma c, and a gamma c, point mutation causing moderate X-linked combined immunodeficiency (XCID), decreased gamma c-Jak3 association. Thus, gamma c mutations in at least some XSCID and XCID patients prevent normal Jak3 activation, suggesting that mutations of Jak3 may result in an XSCID-like phenotype.