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Electrostatic and steric effects underlie acetylation-induced changes in ubiquitin structure and function. Nat Commun 2022; 13:5435. [PMID: 36114200 PMCID: PMC9481602 DOI: 10.1038/s41467-022-33087-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 08/26/2022] [Indexed: 12/29/2022] Open
Abstract
Covalent attachment of ubiquitin (Ub) to proteins is a highly versatile posttranslational modification. Moreover, Ub is not only a modifier but itself is modified by phosphorylation and lysine acetylation. However, the functional consequences of Ub acetylation are poorly understood. By generation and comprehensive characterization of all seven possible mono-acetylated Ub variants, we show that each acetylation site has a particular impact on Ub structure. This is reflected in selective usage of the acetylated variants by different E3 ligases and overlapping but distinct interactomes, linking different acetylated variants to different cellular pathways. Notably, not only electrostatic but also steric effects contribute to acetylation-induced changes in Ub structure and, thus, function. Finally, we provide evidence that p300 acts as a position-specific Ub acetyltransferase and HDAC6 as a general Ub deacetylase. Our findings provide intimate insights into the structural and functional consequences of Ub acetylation and highlight the general importance of Ub acetylation. Ubiquitin is not only a posttranslational modifier but itself is subject to modifications, such as acetylation. Characterization of distinct acetylated ubiquitin variants reveals that each acetylation site has a particular impact on ubiquitin structure and its protein-protein interaction properties.
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Wang Y, Liu R, Liao J, Jiang L, Jeong GH, Zhou L, Polite M, Duong D, Seyfried NT, Wang H, Kiyokawa H, Yin J. Orthogonal ubiquitin transfer reveals human papillomavirus E6 downregulates nuclear transport to disarm interferon-γ dependent apoptosis of cervical cancer cells. FASEB J 2021; 35:e21986. [PMID: 34662469 DOI: 10.1096/fj.202101232rr] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 09/27/2021] [Accepted: 09/28/2021] [Indexed: 02/05/2023]
Abstract
The E6 protein of the human papillomavirus (HPV) underpins important protein interaction networks between the virus and host to promote viral infection. Through its interaction with E6AP, a host E3 ubiquitin (UB) ligase, E6 stirs the protein ubiquitination pathways toward the oncogenic transformation of the infected cells. For a systematic measurement of E6 reprogramming of the substrate pool of E6AP, we performed a proteomic screen based on "orthogonal UB transfer (OUT)" that allowed us to identify the ubiquitination targets of E6AP dependent on the E6 protein of HPV-16, a high-risk viral subtype for the development of cervical cancer. The OUT screen identified more than 200 potential substrates of the E6-E6AP pair based on the transfer of UB from E6AP to the substrate proteins. Among them, we verified that E6 would induce E6AP-catalyzed ubiquitination of importin proteins KPNA1-3, protein phosphatase PGAM5, and arginine methyltransferases CARM1 to trigger their degradation by the proteasome. We further found that E6 could significantly reduce the cellular level of KPNA1 that resulted in the suppression of nuclear transport of phosphorylated STAT1 and the inhibition of interferon-γ-induced apoptosis in cervical cancer cells. Overall, our work demonstrates OUT as a powerful proteomic platform to probe the interaction of E6 and host cells through protein ubiquitination and reveals a new role of E6 in down-regulating nuclear transport proteins to attenuate tumor-suppressive signaling.
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Affiliation(s)
- Yiyang Wang
- Department of Pathophysiology, School of Medicine, Jinan University, Guangzhou, China
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia, USA
| | - Ruochuan Liu
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia, USA
| | - Jia Liao
- Department of Pathophysiology, School of Medicine, Jinan University, Guangzhou, China
| | - Lucen Jiang
- Department of Pathology, The Third Affiliated Hospital of Southern Medical University, Guangzhou, China
| | - Geon H Jeong
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia, USA
| | - Li Zhou
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia, USA
| | - Monica Polite
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia, USA
| | - Duc Duong
- Integrated Proteomics Core, Emory University, Atlanta, Georgia, USA
| | - Nicholas T Seyfried
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Huadong Wang
- Department of Pathophysiology, School of Medicine, Jinan University, Guangzhou, China
| | - Hiroaki Kiyokawa
- Department of Pharmacology, Northwestern University, Chicago, Illinois, USA
| | - Jun Yin
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia, USA
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Udomwan P, Pientong C, Tongchai P, Burassakarn A, Sunthamala N, Roytrakul S, Suebsasana S, Ekalaksananan T. Proteomics Analysis of Andrographolide-Induced Apoptosis via the Regulation of Tumor Suppressor p53 Proteolysis in Cervical Cancer-Derived Human Papillomavirus 16-Positive Cell Lines. Int J Mol Sci 2021; 22:ijms22136806. [PMID: 34202736 PMCID: PMC8268713 DOI: 10.3390/ijms22136806] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 06/22/2021] [Accepted: 06/22/2021] [Indexed: 12/22/2022] Open
Abstract
Regardless of the prophylactic vaccine accessibility, persistent infections of high-risk human papillomaviruses (hr-HPVs), recognized as an etiology of cervical cancers, continues to represent a major health problem for the world population. An overexpression of viral early protein 6 (E6) is linked to carcinogenesis. E6 induces anti-apoptosis by degrading tumor suppressor proteins p53 (p53) via E6-E6-associated protein (E6AP)-mediated polyubiquitination. Thus, the restoration of apoptosis by interfering with the E6 function has been proposed as a selective medicinal strategy. This study aimed to determine the activities of andrographolide (Androg) on the disturbance of E6-mediated p53 degradation in cervical cancer cell lines using a proteomic approach. These results demonstrated that Androg could restore the intracellular p53 level, leading to apoptosis-induced cell death in HPV16-positive cervical cancer cell lines, SiHa and CaSki. Mechanistically, the anti-tumor activity of Androg essentially relied on the reduction in host cell proteins, which are associated with ubiquitin-mediated proteolysis pathways, particularly HERC4 and SMURF2. They are gradually suppressed in Androg-treated HPV16-positive cervical cancer cells. Collectively, the restoration of p53 in HPV16-positive cervical cancer cells might be achieved by disruption of E3 ubiquitin ligase activity by Androg, which could be an alternative treatment for HPV-associated epithelial lesions.
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Affiliation(s)
- Pariyakorn Udomwan
- Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand; (P.U.); (C.P.); (P.T.); (A.B.)
- HPV & EBV and Carcinogenesis Research (HEC) Group, Khon Kaen University, Khon Kaen 40002, Thailand;
| | - Chamsai Pientong
- Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand; (P.U.); (C.P.); (P.T.); (A.B.)
- HPV & EBV and Carcinogenesis Research (HEC) Group, Khon Kaen University, Khon Kaen 40002, Thailand;
| | - Panwad Tongchai
- Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand; (P.U.); (C.P.); (P.T.); (A.B.)
- HPV & EBV and Carcinogenesis Research (HEC) Group, Khon Kaen University, Khon Kaen 40002, Thailand;
| | - Ati Burassakarn
- Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand; (P.U.); (C.P.); (P.T.); (A.B.)
- HPV & EBV and Carcinogenesis Research (HEC) Group, Khon Kaen University, Khon Kaen 40002, Thailand;
| | - Nuchsupha Sunthamala
- HPV & EBV and Carcinogenesis Research (HEC) Group, Khon Kaen University, Khon Kaen 40002, Thailand;
- Department of Biology, Faculty of Science, Mahasarakham University, Mahasarakham 44150, Thailand
| | - Sittiruk Roytrakul
- Functional Ingredients and Food Innovation Research Group, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Pathum Thani 12120, Thailand;
| | - Supawadee Suebsasana
- Faculty of Pharmacy, Thammasat University (Rangsit campus), Pathum Thani 12120, Thailand;
| | - Tipaya Ekalaksananan
- Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand; (P.U.); (C.P.); (P.T.); (A.B.)
- HPV & EBV and Carcinogenesis Research (HEC) Group, Khon Kaen University, Khon Kaen 40002, Thailand;
- Correspondence: ; Tel./Fax: +66-4334-8385
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