Salt, skeletons, and suicide. Focus on 'Hyperosmotic stress regulates the distribution and stability -of myocardin-related transcription factor, a key modulator of the cytoskeleton'

摘要

high NaCl and other sources of hypertonicity are cellular stresses that span evolution. A protective response common to most organisms is cellular accumulation of compatible organic osmolytes, driven by increased transcription of transporters and synthesizing enzymes. In mammalian cells the transcription factor NFAT5 (TonEBP/OREBP) drives the hypertonicity-induced transcription of transporters and synthesizing enzymes that increase protective organic osmolytes (1). NFAT5 has remained the only known osmoprotective mammalian transcription factor. Now, however, Ly et al. (5) have newly identified serum response factor (SRF) as an additional osmoprotective transcription factor whose activation by high NaCl depends on a coregulator, MRTF [megakaryoblastic leukemia (traeslocation) 1, MKL1]. This is exciting news for those of us interested in cellular responses to osmotic stress.