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  • Autophagy regulates levels of tumor suppressor enzyme protein phosphatase 6.

Autophagy regulates levels of tumor suppressor enzyme protein phosphatase 6.

Cancer science (2020-09-25)
Nobuyuki Fujiwara, Shusaku Shibutani, Yusuke Sakai, Toshio Watanabe, Issay Kitabayashi, Hiroko Oshima, Masanobu Oshima, Hisashi Hoshida, Rinji Akada, Tatsuya Usui, Takashi Ohama, Koichi Sato
ABSTRACT

Protein phosphatase 6 (PP6) is an essential serine/threonine protein phosphatase that acts as an important tumor suppressor. However, increased protein levels of PP6 have been observed in some cancer types, and they correlate with poor prognosis in glioblastoma. This raises a question about how PP6 protein levels are regulated in normal and transformed cells. In this study, we show that PP6 protein levels increase in response to pharmacologic and genetic inhibition of autophagy. PP6 associates with autophagic adaptor protein p62/SQSTM1 and is degraded in a p62-dependent manner. Accordingly, protein levels of PP6 and p62 fluctuate in concert under different physiological and pathophysiological conditions. Our data reveal that PP6 is regulated by p62-dependent autophagy and suggest that accumulation of PP6 protein in tumor tissues is caused at least partially by deficiency in autophagy.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Anti-PP2A Antibody, C subunit, Upstate®, from rabbit
Millipore
ANTI-FLAG® antibody produced in rabbit, affinity isolated antibody, buffered aqueous solution