Dynamic regulation of ERK2 nuclear translocation and mobility in living cells

• DOI: 10.1242/jcs.03272
• Publication Date: 2006-11-15T04:03:26Z
• Authors: Mario Costa; Matilde Marchi; Francesco Cardarelli; Anusrhee Roy; Fabio Beltram; Lamberto Maffei; Gian Michele Ratto
• Keywords: Nuclear export signal

The extracellular signal-regulated protein kinase ERK1/2 is a crucial effector linking stimuli to cellular responses: upon phosphorylation ERK [also known as mitogen-activated P42/P44 (MAPK)] concentrates in the nucleus where it activates specific programs of gene expression. Notwithstanding importance this process, little about modalities, time course and regulation exchange between cytoplasm living cells. We visualized dynamic nuclear translocation by expressing low levels (<150 nM) fluorescently tagged ERK2 fibroblasts. Time-lapse imaging demonstrated that concentration can change bidirectionally with constant few minutes. increase requires continuous MEK (also MAPK kinase) activity upstream rapidly reduced operation phosphatases. measured quantitatively speed shuttling determined accelerated after activation, becoming fast enough not be rate-limiting for translocation. Finally, we did diffuse freely diffusion was further impeded phosphorylation, suggesting formation complexes mobility. These results show nucleocytoplasmic trafficking its mobility are dynamically regulated