p21Waf/Cip1, p16INK4a and p14ARF (p19ARF in mice) have been demonstrated to be degraded by REGγ-proteasome pathway in an ATP- and ubiquitin-independent manner in vitro. However, the in vivo roles of REGγ mediated-degradation of p21Waf/Cip1, p16INK4a and p14ARF remain unclear. In this study, we showed enhanced expression of p21Waf/Cip1, p16INK4a and p19ARF in multiple tissues from REGg–/– mice compared to REGg+/+ mice. Furthermore, we examined the expression of p21Waf/Cip1, p16INK4a and p14ARF in different cancer tissues and observed that the REGγ protein levels were highly expressed in different human cancers while the level of p21Waf/Cip1, p16INK4a and p14ARF appears to be inversely correlated. These results demonstrate that REGγ may exert its function in physiological and pathological conditions through degradation of p21Waf/Cip1, p16INK4a and p14ARFin vivo.
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L. Li, P. Zhang, H. Wei, W. Wang, L. Yao, Y. Li, L. Zhou, Z. Wang, J. Liu, L. Zhou, A. Amjad, B. Zhang, T. Jing, J. Xiao, Y. Dang and X. Li, "REGγ Mediated Regulation of p21Waf/Cip1, p16INK4a and p14ARF/p19ARFin Vivo," Journal of Cancer Therapy, Vol. 4 No. 5, 2013, pp. 933-938. doi: 10.4236/jct.2013.45104.
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