Perchloric acid-soluble protein (PSP) may play an important role in the reg
ulation of cellular physiological functions because it has been highly cons
erved throughout evolution; however, this role has not been well elucidated
. In previous reports, we suggested that PSP regulates cell proliferation.
In this study, we examined the effect of PSP expression on proliferation of
the normal rat kidney cell line NRK-52E, the rat hepatocyte cell line RLN-
10, and the rat hepatoma cell line dR-Lh-84. Cells transfected with pcDNA-s
ense-PSP (pcDNA-S-PSP) over-expressed PSP mRNA and protein, and cell prolif
eration of the transfected cells was suppressed compared with that of cells
transfected with pcDNA-empty (pcDNA-E). Cell viability of pcDNA-S-PSP-tran
sfected cells was similar to that of pcDNA-E-transfected cells. Thus, over-
expression of PSP suppresses cell proliferation without any influence on ce
ll viability. These findings are the first to report an inhibitory activity
of PSP on cell proliferation.