Presence and structure‐activity relationship of intrinsically disordered regions across mucins

Abstract

Abbreviations: AMOP, adhesion-associated domain in MUC4 and other proteins domain; CH, charge hydropathy; D 2 P 2 , database of disordered protein predictions; ECM, extracellular matrix; EGF, epidermal growth factor-like domain; IDP, intrinsically disordered protein; IDR, intrinsically disordered region; MoRF, molecular recognition feature; NIDO, nidogen-like domain; PPI, protein-protein interaction; PTM, posttranslational modification; PTS sequence, proline, threonine and serine sequence; SEA, sea-urchin sperm protein enterokinase and agrin module; TM, transmembrane; VNTR, variable number of tandem repeat domain; vWD, von Willebrand factor D domain. AbstractMany members of the mucin family are evolutionarily conserved and are often aberrantly expressed and glycosylated in various benign and malignant pathologies leading to tumor invasion, metastasis, and immune evasion. The large size and extensive glycosylation present challenges to study the mucin structure using traditional methods, including crystallography. We offer the hypothesis that the functional versatility of mucins may be attributed to the presence of intrinsically disordered regions (IDRs) that provide dynamism and flexibility and that the IDRs offer potential therapeutic targets. Herein, we examined the links between the mucin structure and function based on IDRs, posttranslational modifications (PTMs), and potential impact on their interactome. Using sequence-based bioinformatics tools, we observed that mucins are predicted to be moderately (20%-40%) to highly (>40%) disordered and many conserved mucin domains could be disordered. Phosphorylation sites overlap with IDRs throughout the mucin sequences. Additionally, the majority of predicted O-and N-glycosylation sites in the tandem repeat regions occur within IDRs and these IDRs contain a large number of functional motifs, that is, molecular recognition features (MoRFs), which directly influence protein-protein interactions (PPIs).This investigation provides a novel perspective and offers an insight into the complexity and dynamic nature of mucins. K E Y W O R D Sintrinsically disordered protein, glycoprotein, protein-protein interaction, protein structure 1940 | CARMICHEAL Et AL.

Characterization of recombinant β subunit of human MUC4 mucin (rMUC4β)

“…The decreased hydrophobic residues make the protein less susceptible to present a hydrophobic ordered core 49 , 50 . In a recent study analyzing the intrinsically disordered structures of mucins, we reported that MUC4 is 77% disordered; the study also highlighted the vWD domain as a highly disordered domain 51 . However, these prediction studies are based on apomucin backbones, and the impact of glycosylation on the intrinsically disordered content of mucins (including MUC4) remains unexplored and remains to be discerned.…”

Global population genomics of two subspecies ofCryptosporidium hominisduring 500 years of evolution

“…We noted the gene encodes a large intrinsically disordered region (Supplementary Fig. 7) which is a consistent feature of mucin proteins 36 , whose structural confirmation is influenced by post-translation glycosylation 37 . Noting this, we did identify eight novel glycosylation sites in C. h. aquapotentis CHUDEA2_430 haplotypes not found in C. h. hominis (Supplementary Fig 5).…”

Characterization of Recombinant β Subunit of Human MUC4 Mucin (rMUC4β)

“…The decreased hydrophobic residues make the protein less susceptible to present a hydrophobic ordered core 49,50 . A previous study analyzing the intrinsically disordered structures of mucins has shown that MUC4 is 77% disordered; it also highlighted the vWD domain as a highly disordered domain 51 . Although the recombinant protein is nonglycosylated, protein-protein interaction studies using in vitro and in silico analysis showed MUC4 interaction with EGFR and HER2, as previously reported by native protein [17][18][19]52 .…”