title: The prolyl isomerase Pin1 stabilizes the human T-cell leukemia virus type 1 (HTLV-1) Tax oncoprotein and promotes malignant transformation.
abstract: The HTLV Tax protein is crucial for viral replication and malignant transformation. We investigated the possible role of peptidyl prolyl isomerase Pin1 in the positive regulation of the human T-cell leukemia virus type 1 Tax. Pin1 is highly expressed in adult T-cell leukemia (ATL) cells expressing Tax protein and forced expression of Pin1 in turn increases the Tax protein expression. Pin1 prolonged the protein half-life of Tax by suppressing the ubiquitination and subsequent lysosomal degradation of Tax. Pin1 interacts with phosphorylated Tax on its Ser160-Pro motif at the mitotic phase. Finally, we found that Pin1 plays a supporting role in Tax-mediated cell transformation. Our current study demonstrates an important role for Pin1 in the post-translational regulation of Tax and suggests that the targeting of Pin1 may offer a new insight into the pathogenesis of HTLV-1 related diseases.
authors.affiliation: AIDS Research Center, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan.
authors.forename: Soo-Jin
authors.initials: SJ
authors.lastname: Jeong
authors.forename: Akihide
authors.initials: A
authors.lastname: Ryo
authors.forename: Naoki
authors.initials: N
authors.lastname: Yamamoto