TY - JOUR
T1 - Calcineurin-mediated dephosphorylation of c-Jun Ser-243 is required for c-Jun protein stability and cell transformation
AU - Huang, C. C.
AU - Wang, J. M.
AU - Kikkawa, U.
AU - Mukai, H.
AU - Shen, M. R.
AU - Morita, I.
AU - Chen, B. K.
AU - Chang, W. C.
N1 - Funding Information:
Expression plasmid of pEF-HA-Ubi was a gift from Dr Ying Li (Department of Biological Chemistry, University of California, Irvine, CA, USA). We thank Dennis Wang (Department of Biological Chemistry, University of California, Irvine, CA, USA) and Jeffrey K Huang (Department of Veterinary Medicine, University of Cambridge) for critical review of this manuscript. This work was supported in part by NSC 95-2320-B-006-071-MY2, and the Ministry of Education Program for Promoting Academic Excellence of University under Grant 91-B-FA09-1-4 of the Republic of China, National Cheng Kung University Project of Promoting Academic Excellence and Developing World Class Research Centers and the summer program of Interchange Association Japan and National Science Council.
PY - 2008/4/10
Y1 - 2008/4/10
N2 - The proto-oncogene c-Jun plays an important role in regulating tumor progression. We previously reported that the serine/threonine phosphatase calcineurin (CaN, also called PP2B) dephosphorylates the C-terminus (Ser-243) of c-Jun, resulting in the increase in c-Jun and Sp1 interaction, and subsequent c-Jun-induced gene expression. Here, we demonstrate the interaction of c-Jun and CaN in the nucleus of living cells by fluorescence resonance energy transfer assay and that this interaction is mediated through the calmodulin-binding domain of CaN. Furthermore, c-Jun protein stability was altered by CaN-mediated dephosphorylation at the Ser-243 site of c-Jun. The half-life of the c-Jun mutant, c-Jun-S243A was longer than that of the wild-type c-Jun. Moreover, silencing of endogenous CaN expression led to increased c-Jun ubiquitination and decreased stability. In 46% of clinical cervical tissue samples obtained from patients with cervical cancer, enhanced c-Jun and CaN expression, as well as decreased phospho-Ser-243 expression levels were detected. Our results suggest that CaN stabilizes c-Jun by dephosphorylating c-Jun at Ser-243 to enhance its tumorigenic ability.
AB - The proto-oncogene c-Jun plays an important role in regulating tumor progression. We previously reported that the serine/threonine phosphatase calcineurin (CaN, also called PP2B) dephosphorylates the C-terminus (Ser-243) of c-Jun, resulting in the increase in c-Jun and Sp1 interaction, and subsequent c-Jun-induced gene expression. Here, we demonstrate the interaction of c-Jun and CaN in the nucleus of living cells by fluorescence resonance energy transfer assay and that this interaction is mediated through the calmodulin-binding domain of CaN. Furthermore, c-Jun protein stability was altered by CaN-mediated dephosphorylation at the Ser-243 site of c-Jun. The half-life of the c-Jun mutant, c-Jun-S243A was longer than that of the wild-type c-Jun. Moreover, silencing of endogenous CaN expression led to increased c-Jun ubiquitination and decreased stability. In 46% of clinical cervical tissue samples obtained from patients with cervical cancer, enhanced c-Jun and CaN expression, as well as decreased phospho-Ser-243 expression levels were detected. Our results suggest that CaN stabilizes c-Jun by dephosphorylating c-Jun at Ser-243 to enhance its tumorigenic ability.
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U2 - 10.1038/sj.onc.1210888
DO - 10.1038/sj.onc.1210888
M3 - Article
C2 - 17952113
AN - SCOPUS:42049106500
VL - 27
SP - 2422
EP - 2429
JO - Oncogene
JF - Oncogene
SN - 0950-9232
IS - 17
ER -