Identification of a procarboxypeptidase A‐truncated protease E binary complex in human pancreatic juice

Moulard, Maxime; Kerfélec, Brigitte; Mallet, Bernard; Chapus, Catherine

doi:10.1016/0014-5793(89)80712-4

Cited by 13 publications

(6 citation statements)

References 24 publications

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“…Subunit 111 in the procarboxypeptidase A-S6 complex Subunit III is secreted by ruminant pancreas in association with procarboxypeptidase A and chymotrypsinogen C. In non-ruminant species procarboxypeptidase A is found either as a monomer (Guy-Crotte et al, 1988;Moulard et al, 1989) or, for example in the case of the porcine enzyme, associated with zymogen E (Martinez et al, 1981). Tryptic activation of the porcine binary complex does not result in the release of protease E, suggesting that both zymogen and enzyme bind to the complex in the same manner.…”

Section: Structural Bases Of Subunit 111 Inactivitymentioning

confidence: 99%

“…The presence of the ternary complex in the pancreatic juice of ruminants has been tentatively associated with some specific features of digestion in these animals Michon et al, 1991b); subunit IH and the C-type chymotrypsinogen have been shown to protect procarboxypeptidase A, at least partially, against the acidic conditions in the duodenum of ruminants. A glycosylated form of subunit III, secreted both as a monomer (Guy-Crotte et al, 1988) and as a binary complex in association with procarboxypeptidase A (Moulard et al, 1989) has also been observed in human pancreatic juice. The proCPA-S6 ternary complex of ruminants can be reversibly dissociated under mild conditions into its constitutive subunits (Puigserver and Desnuelle, 1975;Kerfelec et al, 1984) and the resulting free proteins have been extensively studied (for a review, see Chapus et al, 1988).…”

Section: Introductionmentioning

confidence: 95%

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Crystal structure of bovine procarboxypeptidase A-S6 subunit III, a highly structured truncated zymogen E.

et al. 1994

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Subunit III, a defective serine endopeptidase lacking the typical N‐terminal hydrophobic dipeptide is secreted by the pancreas of ruminant species as part of the bovine ternary complex procarboxypeptidase A‐S6. Two monoclinic crystal forms were obtained and subsequently used to solve its X‐ray structure. The highest resolution model of subunit III was refined at 1.7 A resolution to a crystallographic R‐factor of 18.4%, with r.m.s. bond deviations from ideality of 0.012 A. About 80% of the model presents the characteristic architecture of trypsin‐like proteases. The remaining zones, however, have well‐defined, unique conformations. The regions from residues 70 to 80 and from 140 to 155 present maximum distances of 16 and 18 A relative to serine proteases and zymogens. Comparisons with the structures of porcine elastase 1 and chymotrypsinogen A indicate that the specific binding pocket of subunit III adopts a zymogen‐like conformation and thus provide a basis for its inactivity. In general, the structural analysis of subunit III strongly suggests that it corresponds to a truncated version of a new class of highly structured elastase‐like zymogen molecules. Based on the structures of subunit III and elastase 1, it is concluded that large concerted movements are necessary for the activation of zymogen E.

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Section: Structural Bases Of Subunit 111 Inactivitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 95%

Crystal structure of bovine procarboxypeptidase A-S6 subunit III, a highly structured truncated zymogen E.

et al. 1994

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“…Due to evolutionary mutations, CELA1 is not expressed in the human pancreas and CELA2B is an inactive protease [12,13,14]. CELA2A and CELA3B bind to proCPA1 and CELA3B also binds to proCPA2 [11,15,16,17]. Even though CELA3A is 92% identical with CELA3B in its primary structure, it does not form tight complexes with proCPA1 or proCPA2 [11].…”

Section: Introductionmentioning

confidence: 99%

Genetic Analysis of Human Chymotrypsin-Like Elastases 3A and 3B (CELA3A and CELA3B) to Assess the Role of Complex Formation between Proelastases and Procarboxypeptidases in Chronic Pancreatitis

Párniczky

Hegyi

Tóth

et al. 2016

IJMS

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Human chymotrypsin-like elastases 3A and 3B (CELA3A and CELA3B) are the products of gene duplication and share 92% identity in their primary structure. CELA3B forms stable complexes with procarboxypeptidases A1 and A2 whereas CELA3A binds poorly due to the evolutionary substitution of Ala241 with Gly in exon 7. Since position 241 is polymorphic both in CELA3A (p.G241A) and CELA3B (p.A241G), genetic analysis can directly assess whether individual variability in complex formation might alter risk for chronic pancreatitis. Here we sequenced exon 7 of CELA3A and CELA3B in a cohort of 225 subjects with chronic pancreatitis (120 alcoholic and 105 non-alcoholic) and 300 controls of Hungarian origin. Allele frequencies were 2.5% for CELA3A p.G241A and 1.5% for CELA3B p.A241G in controls, and no significant difference was observed in patients. Additionally, we identified six synonymous variants, two missense variants, a gene conversion event and ten variants in the flanking intronic regions. Variant c.643-7G>T in CELA3B showed an association with alcoholic chronic pancreatitis with a small protective effect (OR = 0.59, 95% CI = 0.39–0.89, p = 0.01). Functional analysis of missense variants revealed no major defects in secretion or activity. We conclude that variants affecting amino-acid position 241 in CELA3A and CELA3B are not associated with chronic pancreatitis, indicating that changes in complex formation between proelastases and procarboxypeptidases do not alter pancreatitis risk.

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“…25 and references therein). A similar defective elastase was detected in binary complexes with proCPA1 from human pancreas (34). Subsequent studies revealed that subunit III was a purification artifact resulting from the autolytic cleavage of proproteinase E by small amounts of active proteinase E (26 -28).…”

Section: Resultsmentioning

confidence: 91%

Complex Formation of Human Proelastases with Procarboxypeptidases A1 and A2

Szabó¹,

Pilsak

Bence³

et al. 2016

Journal of Biological Chemistry

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The pancreas secretes digestive proenzymes typically in their monomeric form. A notable exception is the ternary complex formed by proproteinase E, chymotrypsinogen C, and procarboxypeptidase A (proCPA) in cattle and other ruminants. In the human and pig pancreas binary complexes of proCPA with proelastases were found. To characterize complex formation among human pancreatic protease zymogens in a systematic manner, we performed binding experiments using recombinant proelastases CELA2A, CELA3A, and CELA3B; chymotrypsinogens CTRB1, CTRB2, CTRC, and CTRL1; and procarboxypeptidases CPA1, CPA2, and CPB1. We found that proCELA3B bound not only to proCPA1 (K D 43 nM) but even more tightly to proCPA2 (K D 18 nM), whereas proCELA2A bound weakly to proCPA1 only (K D 152 nM). Surprisingly, proCELA3A, which shares 92% identity with proCELA3B, did not form stable complexes due to the evolutionary replacement of Ala 241 with Gly. The polymorphic nature of position 241 in both CELA3A (ϳ4% Ala 241 alleles) and CELA3B (ϳ2% Gly 241 alleles) points to individual variations in complex formation. The functional effect of complex formation was delayed procarboxypeptidase activation due to increased affinity of the inhibitory activation peptide, whereas proelastase activation was unchanged. We conclude that complex formation among human pancreatic protease zymogens is limited to a subset of proelastases and procarboxypeptidases. Complex formation stabilizes the inhibitory activation peptide of procarboxypeptidases and thereby increases zymogen stability and controls activation.The exocrine pancreas produces digestive enzymes including serine-and metalloproteases secreted as inactive precursors (zymogens) that attain their active form in the duodenum. Physiological activation of protease zymogens is initiated by enteropeptidase-mediated activation of trypsinogen to trypsin followed by trypsin-mediated activation of chymotrypsinogens, proelastases, and procarboxypeptidases (1). Full activation of human procarboxypeptidases A1 (proCPA1) 2 and A2 (proCPA2) requires additional cleavages by chymotrypsin C (CTRC) to facilitate dissociation of the inhibitory activation peptide (2). Renewed interest in digestive protease physiology was spurred by the recognition that mutations in cationic trypsinogen (PRSS1), the pancreatic secretory trypsin inhibitor (SPINK1), CTRC and CPA1 are strongly associated with chronic pancreatitis in humans (3-6). At the same time, information obtained from genome and pancreatic transcriptome sequencing allowed correct annotation of the full complement of digestive protease isoforms and opened up avenues for investigations using genetically-defined recombinant enzymes. These studies, in turn, led to novel insight into digestive protease function such as the central role of CTRC in the regulation of human trypsinogen (7-9) and procarboxypeptidase activation (2), the role of mesotrypsin (PRSS3) in degrading trypsin inhibitors (10, 11), and the significance of mutation-induced digestive protease misfolding in acinar ce...

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Identification of a procarboxypeptidase A‐truncated protease E binary complex in human pancreatic juice

Cited by 13 publications

References 24 publications

Crystal structure of bovine procarboxypeptidase A-S6 subunit III, a highly structured truncated zymogen E.

Crystal structure of bovine procarboxypeptidase A-S6 subunit III, a highly structured truncated zymogen E.

Genetic Analysis of Human Chymotrypsin-Like Elastases 3A and 3B (CELA3A and CELA3B) to Assess the Role of Complex Formation between Proelastases and Procarboxypeptidases in Chronic Pancreatitis

Complex Formation of Human Proelastases with Procarboxypeptidases A1 and A2

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