Quantitative Analysis of Ubiquitinated Proteins in Human Pituitary and Pituitary Adenoma Tissues.

Shehua Qian,Miaolong Lu,Xianquan Zhan,Xiaohan Zhan,Dominic M Desiderio,Na Li,Xuejun Li,Ying Long

doi:10.3389/fendo.2019.00328

Abstract

Protein ubiquitination is an important post-translational modification that is associated with multiple diseases, including pituitary adenomas (PAs). Protein ubiquitination profiling in human pituitary and PAs remains unknown. Here, we performed the first ubiquitination analysis with an anti-ubiquitin antibody (specific to K-ε-GG)-based label-free quantitative proteomics method and bioinformatics to investigate protein ubiquitination profiling between PA and control tissues. A total of 158 ubiquitinated sites and 142 ubiquitinated peptides in 108 proteins were identified, and five ubiquitination motifs were found. KEGG pathway network analysis of 108 ubiquitinated proteins identified four statistically significant signaling pathways, including PI3K-AKT signaling pathway, hippo signaling pathway, ribosome, and nucleotide excision repair. R software Gene Ontology (GO) analysis of 108 ubiquitinated proteins revealed that protein ubiquitination was involved in multiple biological processes, cellular components, and molecule functions. The randomly selected ubiquitinated 14-3-3 zeta/delta protein was further analyzed with Western blot, and it was found that upregulated 14-3-3 zeta/delta protein in nonfunctional PAs might be derived from the significantly decreased level of its ubiquitination compared to control pituitaries, which indicated a contribution of 14-3-3 zeta/delta protein to pituitary tumorigenesis. These findings provided the first ubiquitinated proteomic profiling and ubiquitination-involved signaling pathway networks in human PAs. This study offers new scientific evidence and basic data to elucidate the biological functions of ubiquitination in PAs, insights into its novel molecular mechanisms of pituitary tumorigenesis, and discovery of novel biomarkers and therapeutic targets for effective treatment of PAs.

Highlights

Pituitary adenomas (PAs) are a common type of intracranial tumor [1] that accounts for about 10% of intracranial tumors [2]
The ubiquitination site was localized to amino acid residue K∗11, and the ubiquitination level was significantly increased in pituitary adenoma (PA) compared to controls (Table 2)
The ubiquitination site was localized to amino acid residue K∗85, and the protein was ubiquitinated in PAs but not in controls (Table 2)

Summary

Introduction

Pituitary adenomas (PAs) are a common type of intracranial tumor [1] that accounts for about 10% of intracranial tumors [2]. Clinical manifestations include abnormalities of hormone secretion, pituitary apoplexy, compressing syndromes of tumor that surrounds the pituitary gland, and other anterior pituitary dysfunctions. Because an FPA has its secondary symptoms and signs of excessive secretion of tumor hormones, it is diagnosed and treated at an earlier stage. NFPAs do not have any hormone hypersecretion and are more difficult to diagnosis [4]. An NFPA usually has a larger volume at the time of diagnosis, and is often characterized by hypophysis dysfunction, visual field defect, and headache [5]. A PA is commonly a benign tumor [6], secondary symptoms are caused by a large number of hormones produced by FPA and compression of surrounding tissues— causing vision loss, headaches, and so on by NFPA [7].

Methods

Results

Conclusion