Mammalian small heat shock protein (s-hsp) has been suggested to parti
cipate not only in stress tolerance but also in the growth regulation
and differentiation of cells. To confirm the role of s-hsp in cell gro
wth, we investigated the relationship between the expression of hsp26
and yeast cell growth. Cells lacking constitutive hsp70, ssa1ssa2, hav
e 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 dou
bling times were different from one another. The amount of hsp26 was c
losely linked to the doubling time of ssa1ssa2 cells. This result sugg
ests that the expression of hsp26 modulates the growth rate of yeast c
ells lacking constitutive hsp70, similarly to mammalian cells.