Hattori H, Kaneda T, Lokeshwar B, Laszlo A, Ohtsuka K
Department of Oral Surgery, Nagoya University School of Medicine, Japan.
J Cell Sci. 1993 Mar;104 ( Pt 3):629-38. doi: 10.1242/jcs.104.3.629.
We have previously reported that a novel 40 kDa protein is induced by heat shock and several environmental stresses in mammalian and avian cells and that the N-terminal amino acid sequence of this 40 kDa protein has homology with the bacterial DnaJ heat-shock protein. We have purified this protein (40 kDa heat-shock protein, hsp40) from HeLa cells by modified two-dimensional gel electrophoresis and generated a polyclonal antibody against hsp40. This antibody was highly specific for human hsp40 and cross-reacted weakly with rat and Chinese hamster hsp40. Indirect immunofluorescence revealed that the hsp40 in HeLa cells accumulates in the nucleus, especially in the nucleolus, during heat shock and returns to the cytoplasm during the recovery period. The kinetics of the accumulation in the nucleoli and subsequent return to the cytoplasm of hsp40 was similar to that of hsp70. In addition, hsp40 was co-localized with hsc70(p73) in heat-shocked HeLa cells as demonstrated by double immunofluorescence staining. These results suggest that hsp40 (a DnaJ homologue) and hsp70 (a DnaK homologue) may act in concert to repair (refold) denatured proteins and protein aggregates in the nuclei and nucleoli of heat-shocked HeLa cells.
我们之前报道过，一种新的40 kDa蛋白在哺乳动物和禽类细胞中受热休克及几种环境应激诱导产生，且该40 kDa蛋白的N端氨基酸序列与细菌DnaJ热休克蛋白具有同源性。我们通过改良的二维凝胶电泳从HeLa细胞中纯化了这种蛋白（40 kDa热休克蛋白，hsp40），并制备了抗hsp40的多克隆抗体。该抗体对人hsp40具有高度特异性，与大鼠和中国仓鼠的hsp40有较弱的交叉反应。间接免疫荧光显示，HeLa细胞中的hsp40在热休克期间积聚在细胞核中，尤其是核仁中，恢复期回到细胞质。hsp40在核仁中积聚及随后回到细胞质的动力学与hsp70相似。此外，双重免疫荧光染色表明，在热休克的HeLa细胞中，hsp40与hsc70(p73)共定位。这些结果表明，hsp40（一种DnaJ同源物）和hsp70（一种DnaK同源物）可能协同作用，修复（重新折叠）热休克的HeLa细胞核和核仁中变性的蛋白质和蛋白质聚集体。
