Promoting anti-tumor immunity by targeting TMUB1 to modulate PD-L1 polyubiquitination and glycosylation

Immune checkpoint blockade therapies targeting the PD-L1/PD-1 axis have demonstrated clear clinical benefits. Improved understanding of the underlying regulatory mechanisms might contribute new insights into immunotherapy. Here, we identify transmembrane and ubiquitin-like domain-containing protein 1 (TMUB1) as a modulator of PD-L1 post-translational modifications in tumor cells. Mechanistically, TMUB1 competes with HECT, UBA and WWE domain-containing protein 1 (HUWE1), a E3 ubiquitin ligase, to interact with PD-L1 and inhibit its polyubiquitination at K281 in the endoplasmic reticulum. Moreover, TMUB1 enhances PD-L1 N-glycosylation and stability by recruiting STT3A, thereby promoting PD-L1 maturation and tumor immune evasion. TMUB1 protein levels correlate with PD-L1 expression in human tumor tissue, with high expression being associated with poor patient survival rates. A synthetic peptide engineered to compete with TMUB1 significantly promotes antitumor immunity and suppresses tumor growth in mice. These findings identify TMUB1 as a promising immunotherapeutic target.


Field-specific reporting
Please select the one below that is the best fit for your research. If you are not sure, read the appropriate sections before making your selection.

Life sciences
Behavioural & social sciences Ecological, evolutionary & environmental sciences For a reference copy of the document with all sections, see nature.com/documents/nr-reporting-summary-flat.pdf

Life sciences study design
All studies must disclose on these points even when the disclosure is negative. Reporting for specific materials, systems and methods The PD-L1-IP mass spectrometry proteomics data have been deposited to the ProteomeXchange Consortium via the PRIDE partner repository with the dataset identifier PXD031702. All data are included in the Supplemental Information or available from the authors upon reasonable requests In this study, patients in this study were differentiated by biological sex, in which all breast cancer patients were female, while the gender composition of gastric cancer patients was reported in Supplementary Table 4. Only female patients were considered in all parts of this study involving breast cancer. The part of this study involving gastric cancer did not design the experiment for gender or sex.
Information about breast and gastric cancer patients is included in Supplementary Table 3 and Supplementary Table 4, including age, gender of both cancers and HER2\ER\PR positivity of breast cancer patients.
All samples were collected from patients with informed consent, and all related procedures were performed with the approval of the internal review and ethics boards of SYSUCC or Ethics Committee of the Second Affiliated Hospital, School of Medicine Zhejiang University. Patients were recruited with no perceived bias. All patients were not treated with adjuvant radiotherapy or chemotherapy before operation.All patients were provided with informed written consents for obtaining study specimens.
The internal review and ethics boards of SYSUCC, Ethics Committee of the Second Affiliated Hospital, School of Medicine Zhejiang University No statistical method was used to predetermine sample size. Sample size was chosen based on previous experience and standards in the field. All of the experiments were repeated least 3 times. The sample size for in vitro (n>=3) and in vivo (n>=5) are typical in the field. We determined the sample size based on previous published studies in the field over the past years (Aifu Lin, et al., Nat Cell Biol. 2016;Aifu Lin, et al., Nat Cell Biol, 2017;Xin Zheng, et al. EMBO J, 2017;Lingjie Sang, et al., Mol Cell, 2018;Lingjie Sang, et al., Nat Metab, 2021).
There are no data exclusions.
For each representative image/data, experiments were performed at least three times with similar results unless otherwise noted in the manuscript.
Samples and organisms were randomly allocated to experimental groups. No specific randomization protocol has been used. Mice were ageand sex matched.
No specific blinding was applied since all experiments were assigned into groups including relevalant controls and analysis was done objectively and without bias.

March 2021
We require information from authors about some types of materials, experimental systems and methods used in many studies. Here, indicate whether each material, system or method listed is relevant to your study. If you are not sure if a list item applies to your research, read the appropriate section before selecting a response.