Aberrant Activation of JAK/STAT Pathway Components in Response to G-CSF, Interferon-a/p and Interferon-y in NFS-60 Cells

Abstract

There is evidence that the cellular responses to cytokines, such as granulocyte colony stimulating factor (G-CSF) and interferons, depend on prior activation of components of the JAK/STAT signalling pathway. We report here that the myeloid cell line NFS-60 shows aberrant JAK/STAT signalling yet elicits expected biological responses to G-CSF and interferons-α/β and γ. Instead of increased phosphorylation of JAKl and JAK2 in response to G-CSF and interf eron-y, and JAK1 and JAk2 in response to interferon-α/β we observed only an increase of phosphorylation of Tyk2 in response to all of these cytokines in NFS-60 cells. The subset of STAT proteins being activated in response to these cytokines wa..