β-Trefoil structure enables interactions between lectins and protease inhibitors that regulate their biological functions

Žurga, Simon; Pohleven, Jure; Kos, Janko; Sabotič, Jerica

doi:10.1093/jb/mvv025

Cited by 23 publications

(13 citation statements)

References 26 publications

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“…ppGalNAc-T3 had an enhancing effect on Gal-T activity of dC1GalT at high concentration of substrate and an inhibitory effect at low substrate concentration that affected V max and K m . Consistent with the activator effect of the ppGalNAc-T3 lectin domain (␤-trefoil fold) on dC1GalT activity, lectins from Macrolepiota procera and Clitocybe nebularis, which are fungal ␤-trefoil proteins, were found to enhance protease activity of trypsin and papain (26).…”

Section: Lectin Functions In Glycan Biosynthesismentioning

confidence: 58%

Functional control of polypeptide GalNAc-transferase 3 through an acetylation site in the C-terminal lectin domain

Lorenz¹,

Cejas²,

Bennett

et al. 2017

Biological Chemistry

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O-GalNAc glycans are important structures in cellular homeostasis. Their biosynthesis is initiated by members of the polypeptide GalNAc-transferase (ppGalNAc-T) enzyme family. Mutations in ppGalNAc-T3 isoform cause diseases (congenital disorders of glycosylation) in humans. The K626 residue located in the C-terminal β-trefoil fold of ppGalNAc-T3 was predicted to be a site with high likelihood of acetylation by CBP/p300 acetyltransferase. We used a site-directed mutagenesis approach to evaluate the role of this acetylation site in biological properties of the enzyme. Two K626 mutants of ppGalNAc-T3 (T3K626Q and T3K626A) had GalNAc-T activities lower than that of wild-type enzyme. Direct and competitive interaction assays revealed that GalNAc recognition by the lectin domain was altered in the mutants. The presence of GlcNAc glycosides affected the interaction of the three enzymes with mucin-derived peptides. In GalNAc-T activity assays, the presence of GlcNAc glycosides significantly inhibited activity of the mutant (T3K626Q) that mimicked acetylation. Our findings, taken together, reveal the crucial role of the K626 residue in the C-terminal β-trefoil fold in biological properties of human ppGalNAc-T3. We propose that acetylated residues on ppGalNAc-T3 function as control points for enzyme activity, and high level of GlcNAc glycosides promote a synergistic regulatory mechanism, leading to a metabolically disordered state.

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Section: Lectin Functions In Glycan Biosynthesismentioning

confidence: 58%

Functional control of polypeptide GalNAc-transferase 3 through an acetylation site in the C-terminal lectin domain

Lorenz¹,

Cejas²,

Bennett

et al. 2017

Biological Chemistry

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“…In addition, it can interact with fungal protease inhibitors sharing the β-trefoil fold, modulating their activity. It is particularly interesting that CNL interacts with the trypsin-specific protease inhibitor cnispin, which is also expressed in fruiting bodies of C. nebularis [16,17]. Complex formation between CNL and cnispin has been demonstrated by glutaraldehyde cross-linking in vitro [17].…”

Section: Cnl Functionmentioning

confidence: 99%

CNL–Clitocybe nebularis Lectin—The Fungal GalNAcβ1-4GlcNAc-Binding Lectin

Sabotič

Kos

2019

Molecules

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Clitocybe nebularis lectin (CNL) is present in fruiting bodies of clouded agaric along with several similar isolectins that are all small and stable proteins. It is a beta-trefoil type lectin forming homodimers that are essential for its functionality. It binds specifically N,N′-diacetyllactosediamine (GalNAcβ1-4GlcNAc, LacDiNac) and human blood group A determinant-containing glycan epitopes. Its most probable function is to defend fruiting bodies against predators and parasites. In addition, an endogenous regulatory function is possible for CNL, as indicated by its interaction with fungal protease inhibitors sharing the beta-trefoil fold. CNL is toxic to insects, nematodes and amoebae, as well as to leukemic T-cell lines. Bivalent carbohydrate binding is essential for the toxicity of CNL, against both invertebrates and cancer-derived cell lines. In addition, CNL exhibits potent immunostimulation of human dendritic cells, resulting in a strong T helper cell type 1 response. Based on its unique characteristics, CNL is a promising candidate for applications in human and veterinary medicine as well as in agriculture, for plant protection.

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“…[16][17][18][19][20] Furthermore, mycocypins are resistant to proteolytic digestion by the highly non-specific proteinase K although they do not inhibit its proteolytic activity. 21 Family I66 comprises the trypsin-specific inhibitors mycospins: cnispin 22 (Cnp) from Clitocybe nebularis and cospin 23 (PIC) from Coprinopsis cinerea, as well as a representative from Lentinula edodes. 24 These inhibitors are small proteins, the molecular mass of cnispin being 16.4 kDa and that of cospin 16.7 kDa and both with a low isoelectric point around pH 5.…”

Section: Protease Inhibitors From Higher Fungimentioning

confidence: 99%

“…17,22,23,25,26,28 Another layer of regulation of the β-trefoil fungal protease inhibitors mycocypins and mycospins, is indicated by their interaction in vitro with β-trefoil lectins MpL and CNL from the same species, which are also expressed intracellularly and involved in fruiting body defence. 21,27,[33][34][35][36]…”

Section: Functional Variabilitymentioning

confidence: 99%

β-Trefoil Protease Inhibitors Unique to Higher Fungi

Sabotič¹,

Renko²,

Kos³

2019

ACSi

Self Cite

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The cysteine protease inhibitors, clitocypin and macrocypins, from higher fungi (mycocypins), together with the serine protease inhibitors highly specific for trypsin cospin and cnispin from higher fungi (mycospins), display several characteristics that distinguish them from protease inhibitors from other sources. Their high genetic heterogeneity affects their functionality and/or stability and results in numerous protein variants with slightly different inhibitory profiles that influence the type of protease inhibited and/or the strength of inhibition. They possess the β-trefoil fold that shows high plasticity in their utilization of the 11 diverse loops for the inhibition of various families of proteases through different mechanisms of inhibition. Their high versatility is also seen in their regulatory and defence functions and in their potential applications in biotechnology, crop protection and medicine.

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β-Trefoil structure enables interactions between lectins and protease inhibitors that regulate their biological functions

Cited by 23 publications

References 26 publications

Functional control of polypeptide GalNAc-transferase 3 through an acetylation site in the C-terminal lectin domain

Functional control of polypeptide GalNAc-transferase 3 through an acetylation site in the C-terminal lectin domain

CNL–Clitocybe nebularis Lectin—The Fungal GalNAcβ1-4GlcNAc-Binding Lectin

β-Trefoil Protease Inhibitors Unique to Higher Fungi

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