著者

Unno Keiko Kishido Takahiro Hosaka Maho OKADA Shoji

出版者

公益社団法人日本薬学会

雑誌

Biological & pharmaceutical bulletin (ISSN:09186158)

巻号頁・発行日

vol.20, no.12, pp.1240-1244, 1997-12-15

被引用文献数

1 8

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To investigate the role of constitutive hsp70 in protein folding and to probe the supplementation by other hsps in this folding, yeast cells expressing reduced constitutive hsp70 proteins, ssa1ssa2,were transformed with a plasmid expressing a bacterial luciferase protein. With several independent clone cells of transformants, the levels of luciferase activity and some hsps, such as hsp104,hsp90,hsp70 and hsp26,were examined. The luciferase activity was significantly lower in ssa1ssa2 transformants than in the wild type (wt) cell transformed with the same plasmid. Among several clone cells of ssa1ssa2,the cells with higher luciferase activities exhibited higher amounts of Ssa4 which is known to be expressed instead of lacking Ssa1 and Ssa2. The luciferase activity closely correlated with the amount of Ssa proteins, more than with the amount of other hsps. It is suggested that consitutional Ssa "chaperones" are needed for the folding of proteins and, in cells lacking Ssa1 and Ssa2,the increased Ssa4 is thought to partly compensate for their role in the folding of luciferase in vivo.

著者

Unno Keiko Kishido Takahiro Okada Shoji

出版者

公益社団法人日本薬学会

雑誌

Biological & pharmaceutical bulletin (ISSN:09186158)

巻号頁・発行日

vol.21, no.6, pp.631-633, 1998-06-15

被引用文献数

1 4

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Mammalian small heat shock protein (s-hsp) has been suggested to participate not only in stress tolerance but also in the growth regulation and differentiation of cells. To confirm the role of s-hsp in cell growth, we investigated the relationship between the expression of hsp26 and yeast cell growth. Cells lacking constitutive hsp70,ssa1ssa2,have been known to have a poor growth rate and to over-express hsp26 and some other hsps. We obtained several cell clones of ssa1ssa2 whose doubling times were different from one another. The amount of hsp26 was closely linked to the doubling time of ssa1ssa2 cells. This result suggests that the expression of hsp26 modulates the growth rate of yeast cells lacking constitutive hsp70,similarly to mammalian cells.