BAG-1 inhibits p53-induced but not apoptin-induced apoptosis.
BAG-1 has been identified as a Bcl-2-binding protein that inhibits apoptosis, either alone or in co-operation with Bcl-2. Here we show that BAG-1 inhibits p53- induced apoptosis in the human tumour cell line Saos-2. In contrast, BAG-1 was unable to inhibit the p53-independent pathway induced by apoptin, an apoptosis-inducing protein derived from chicken anaemia virus. Whereas BAG-1 seemed to co-operate with Bcl-2 to repress p53-induced apoptosis, co-expression of these proteins had no inhibitory effect on apoptin-induced apoptosis. Moreover, Bcl-2, and to some extent also BAG-1, paradoxically enhanced the apoptotic activity of apoptin. These results demonstrate that p53 and apoptin induce apoptosis through independent pathways, which are differentially regulated by BAG-1 and Bcl-2.
Danen-van Oorschot
A A
AA
Laboratory for Molecular Carcinogenesis, Leiden University, The Netherlands.
den Hollander
A I
AI
Takayama
S
S
Reed
J C
JC
van der Eb
A J
AJ
Noteborn
M H
MH