MDM2 interacts with and downregulates a sarcomeric protein, TCAP.
Recent reports have shown that MDM2 may attenuate hypertrophy of cardiac myocytes. However, mechanism of MDM2 involving in this process is unclear. In this study, we identified a novel specific MDM2-binding protein TCAP by the yeast two-hybrid screen. It was validated by GST pull-down and co-immunoprecipitation assays. Confocal analysis showed that MDM2 and TCAP co-localized in the nucleus, and elevated MDM2 expression could alter the subcellular localization of TCAP. Notably, MDM2 downregulated the protein level of TCAP through the proteasomal pathway, and this downregulation was inhibited by p14(ARF). In addition, our results suggested that the degradation of TCAP by MDM2 was through the ubiquitin-independent pathway. Given that TCAP is a key component involving in the cardiac hypertrophy, the degradation of TCAP by MDM2 might be connected with the roles of MDM2 in cardiac hypertrophy. Further investigation will focus on the biological significance of MDM2-TCAP interaction in cardiac hypertrophy.
Tian
Li-Feng
LF
National Center of Biomedical Analysis, Beijing 100850, China.
Li
Hui-Yan
HY
Jin
Bao-Feng
BF
Pan
Xin
X
Man
Jiang-Hong
JH
Zhang
Pei-Jing
PJ
Li
Wei-Hua
WH
Liang
Bing
B
Liu
Hui
H
Zhao
Jie
J
Gong
Wei-Li
WL
Zhou
Tao
T
Zhang
Xue-Min
XM