Confocal imaging studies cast doubt on nuclear localization of JAK2V617F.

摘要

The most common mutation in myeloproliferative neoplasm (MPN) substitutes a valine to phenylalanine at position 617 of JAK2 (JAK2W617F).Recently, Rinaldi et al reported both a nuclear and cytoplasmic localization of JAK2 in K562 cells. A previous report also indicated that JAK2V617F translocates to the nucleus, where it is proposed to phosphorylate histone H3. These findings remain controversial, in part because of nonspecific binding of the commercial anti-JAK2 antibodies used in most studies. To avoid reliance on antibodies, we also studied the cellular localization of JAK2 wild-type (WT) and V617F expressed as chimeric proteins fused to visible fluorescent proteins (VFP; derivatives of green fluorescent protein). Transfections were performed using an Amaxa electroporation method (Lonza AG) with at least a 60% rate of transfection efficiency in each cell line.