Functional analysis of Hikeshi reveals physiological significance of nuclear Hsp70

Nucleocytoplasmic transport is a basic cellular reaction that plays an important role in regulating cell physiology in eukaryotic cells. Here we show that the identification of one nucleocytoplasmic transport pathway led to the notification of intracellular reaction that has not been acknowledged. Hikeshi was originally identified as a nuclear import carrier of heat stress–induced nuclear import of molecular chaperone Hsp70. We now know that Hikeshi mediates nuclear import of Hsp70 at a variety of different cellular conditions, such as at normal conditions, at proteotoxic conditions, during differentiation, and probably more. Recent studies gradually revealed the physiological significances of Hikeshi-mediated nuclear import of Hsp70.