High-resolution structure of intramolecularly proteolyzed human mucin-1 SEA domain

Noguera, Martín Ezequiel; Jakoncic, Jean; Ermácora, Mario R.

doi:10.1016/j.bbapap.2020.140361

Cited by 11 publications

(16 citation statements)

References 60 publications

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“…Membrane-associated mucins such as MUC1 have a monomeric structure and contain distinct transmembrane domains, which enable them to be incorporated into the apical cell surface of epithelia, as well as a short cytoplasmic tail and a Sea urchin-Enterokinase-Agrin (SEA) domain [ 2 , 4 , 13 ]. The SEA domain joins the tandemly repeated polypeptide region to the transmembrane domain.…”

Section: Introductionmentioning

confidence: 99%

The Relationship between Mucins and Ulcerative Colitis: A Systematic Review

Bankole

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Curtis

et al. 2021

JCM

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Mucins are a family of glycosylated proteins which are the primary constituents of mucus and play a dynamic role in the regulation of the protective mucosal barriers throughout the human body. Ulcerative colitis (UC) is an Inflammatory Bowel Disease (IBD) characterised by continuous inflammation of the inner layer of the large intestine, and in this systematic review we analyse currently available data to determine whether alterations exist in mucin activity in the colonic mucosa of UC patients. Database searches were conducted to identify studies published between 1990 and 2020 that assess the role of mucins in cohorts of UC patients, where biopsy specimens were resected for analysis and control groups were included for comparison. 5497 articles were initially identified and of these 14 studies were systematically selected for analysis, a further 2 articles were identified through citation chaining. Therefore, 16 studies were critically reviewed. 13 of these studies assessed the role of MUC2 in UC and the majority of articles indicated that alterations in MUC2 structure or synthesis had an impact on the colonic mucosa, although conflicting results were presented regarding MUC2 expression. This review highlights the importance of further research to enhance our understanding of mucin regulation in UC and summarises data that may inform future studies.

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Section: Introductionmentioning

confidence: 99%

The Relationship between Mucins and Ulcerative Colitis: A Systematic Review

Bankole

Read

Curtis

et al. 2021

JCM

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“…A time course proteolytic stability experiment revealed that following TEV protease digestion, the molecular weight of the protein shifted from ~22 kDa (corresponding to the 1.2TR) to ~14 kDa (corresponding to the SEA domain) sometime between 24‐ and 48‐h (Figure 1A). Although autoproteolytic activity has been reported for some mucin SEA domains including MUC1, 26 the MUC16 SEA5 domain lacks the GSVV proteolytic cleavage motif and thus is an unlikely explanation for the observed proteolysis. Based on the resultant size of the fragment, the PST rich sequences flanking the SEA5 domain were possibly cleaved by residual protease activity of contaminating proteases, resulting in a stable SEA domain.…”

Section: Resultsmentioning

confidence: 89%

“…The murine SEA domain is 37% identical to that of the human SEA5 domain, which approaches the limitation of ~30%–35% sequence homology for a suitable search model for MR. An additional complication in using the murine MUC16 SEA domain as a MR search model is that NMR models themselves have traditionally been difficult to use for MR 29 . Similarly, the recently published structure of the MUC1 SEA domain could not be determined by MR using an NMR model, even with complete sequence identity 26 . Although NMR models historically have been difficult to use as MR models, refinement with Rosetta has been found to greatly improve the phasing power of NMR models 30 .…”

Section: Resultsmentioning

confidence: 99%

“…to use for MR. 29 Similarly, the recently published structure of the MUC1 SEA domain could not be determined by MR using an NMR model, even with complete sequence identity. 26 Although NMR models historically have been difficult to use as MR models, refinement with Rosetta has been found to greatly improve the phasing power of NMR models. 30 Indeed, Rosetta has emerged as a powerful tool to facilitate MR of difficult targets.…”

Section: Structure Determination Of Muc16 Sea5 Domainmentioning

confidence: 99%

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Crystal structure of a human MUC16 SEA domain reveals insight into the nature of the CA125 tumor marker

et al. 2022

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MUC16 is a membrane bound glycoprotein involved in the progression and metastasis of pancreatic and ovarian cancer. The protein is shed into the serum and the resulting cancer antigen 125 (CA125) can be detected by immunoassays. The CA125 epitope is used for monitoring ovarian cancer treatment progression, and has emerged as a potential target for antibody mediated immunotherapy. The extracellular tandem repeat domain of the protein is composed of repeating segments of heavily glycosylated sequence intermixed with homologous SEA (Sperm protein, Enterokinase and Agrin) domains. Here we report the purification and the first X-ray structure of a human MUC16 SEA domain. The structure was solved by molecular replacement using a Rosetta generated structure as a search model. The SEA domain reacted with three different MUC16 therapeutic antibodies, confirming that the CA125 epitope is localized to the SEA domain. The structure revealed a canonical ferredoxin-like fold, and contained a conserved disulfide bond. Analysis of the relative solvent accessibility of side chains within the SEA domain clarified the assignment of N-linked and O-linked glycosylation sites within the domain. A model of the glycosylated SEA domain revealed two major accessible faces, which likely represent the binding sites of CA125 specific antibodies. The results presented here will serve to accelerate future work to understand the functional role of MUC16 SEA domains and antibody recognition of the CA125 epitope.

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“…Proteolytic SEA domains have a characteristic globular shape constituted by four alpha helix and four beta sheets, in which proteolysis occurs between the second and the third beta sheet (Fig. 3A, B) (11). In humans, mutations affecting the SEA-2 domain of IMPG1 are linked to the development of RP disease (Fig.…”

Section: Resultsmentioning

confidence: 99%

Interphotoreceptor matrix proteoglycans IMPG1 and IMPG2 proteolyze in the SEA domain and reveal localization mutual dependency

Mitchell

Coulter

Geldenhuys

et al. 2022

Preprint

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The interphotoreceptor matrix (IPM) is a specialized extracellular mesh of molecules surrounding the inner and outer segments of the photoreceptor neurons. The interphotoreceptor matrix proteoglycan 1 and 2 (IMPG1 and IMPG2) are major components of the IPM. Both proteoglycans possess SEA (Sperm protein, Enterokinase and Agrin) domains, which are described to support protein proteolysis. Interestingly, humans with mutations in the SEA domains of IMPG1 and IMPG2 are associated with retinitis pigmentosa (RP) vision disease. This work investigates the SEA-mediated proteolysis of IMPG1 and IMPG2 and its significance to IPM physiology. Western blot relative molecular mobility analysis of IMPG1 from retina confirmed protein proteolysis. Point mutations in the SEA domain of IMPG1 inhibit protein proteolysis, as shown in cell culture assays. Likewise, IMPG2 also proteolyzes at the SEA domain generating two subunits: a membrane-attached and an extracellular peptide, as seen by western blot and immunohistochemical assays. Importantly, the extracellular portion of IMPG2 traffics toward the outer segment IPM by a mechanism dependent on IMPG1. These results demonstrate that proteolysis is part of the maturation of IMPG1 and IMPG2, which is important for protein localization and linked to vision diseases. Moreover, the results indicate interdependency between IMPG1 and IMPG2, which helps understand the molecular mechanisms involved in the development of vision diseases in patients with defective IMPG molecules.

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High-resolution structure of intramolecularly proteolyzed human mucin-1 SEA domain

Cited by 11 publications

References 60 publications

The Relationship between Mucins and Ulcerative Colitis: A Systematic Review

The Relationship between Mucins and Ulcerative Colitis: A Systematic Review

Crystal structure of a human MUC16 SEA domain reveals insight into the nature of the CA125 tumor marker

Interphotoreceptor matrix proteoglycans IMPG1 and IMPG2 proteolyze in the SEA domain and reveal localization mutual dependency

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