Affinage

PCSK2

Neuroendocrine convertase 2 · UniProt P16519

Length
638 aa
Mass
70.6 kDa
Annotated
2026-06-10
23 papers in source corpus 10 papers cited in narrative 10 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 5/5 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

PCSK2 (PC2/SPC2) is a subtilisin-related serine protease of neuroendocrine secretory vesicles that converts prohormones into mature bioactive peptides by cleaving at dibasic sites, and its activity is central to endocrine and metabolic regulation (PMID:9192619, PMID:7595521). Genetic loss in mice severely impairs processing of proglucagon, prosomatostatin, and proinsulin in pancreatic alpha, delta, and beta cells, producing fasting hypoglycemia, islet cell hyperplasia, and glucagon deficiency (PMID:9192619), and likewise disrupts processing of brain proneuropeptide Y and intestinal peptides (substance P, somatostatin, GLP-1, GLP-2, peptide YY) with delayed intestinal transit and blunted refeeding (PMID:21092739). Beyond these, PCSK2 uniquely generates dynorphin A-(1-8) from dynorphin A-(1-17) and processes secretogranin II (PMID:14734558). Substrate selection is context-dependent: in colonic enteroendocrine cells, increased PCSK2 expression shifts proglucagon cleavage toward glucagon rather than GLP-1/GLP-2 [PMID:bio_10.1101_2024.12.23.630024]. PCSK2 abundance is set transcriptionally by CREB in arcuate POMC neurons, where it controls alpha-MSH production and energy balance (PMID:35805082), and its catalytic activity is enhanced by the chaperone 7B2/Scg5 (PMID:18439298). A coding variant (R430W) broadens the enzyme's pH optimum, altering substrate processing across physiological pH (PMID:28719828).

Mechanistic history

Synthesis pass · year-by-year structured walk · 8 steps
  1. 1995 Medium

    Establishing where the active enzyme resides addressed whether PCSK2 functions as a granule-localized processing protease and in what physical state.

    Evidence Subcellular fractionation of bovine pituitary and adrenal medulla secretory vesicles with immunoreactivity analysis

    PMID:7595521

    Open questions at the time
    • Does not define catalytic substrates
    • Functional significance of membrane vs soluble partitioning unresolved
  2. 1997 High

    Genetic knockout established PCSK2 as physiologically required for prohormone maturation across multiple islet cell types, defining its core endocrine function and metabolic consequence.

    Evidence Exon 3 deletion knockout mouse, glucose tolerance testing, islet morphology

    PMID:9192619

    Open questions at the time
    • Direct cleavage-site biochemistry not resolved in vivo
    • Cause of alpha/delta cell hyperplasia not mechanistically defined
  3. 2004 Medium

    Loss-of-function in a beta-cell line identified specific peptide substrates, sharpening which cleavages PCSK2 performs uniquely.

    Evidence Delta ribozyme silencing in betaTC-3 cells, dynorphin A-(1-8) measurement, differential proteomics

    PMID:14734558

    Open questions at the time
    • Secretogranin II remains only a candidate substrate
    • Single cell line and single lab
  4. 2008 Medium

    Two studies addressed regulation and tissue distribution: the chaperone 7B2/Scg5 was shown to raise PCSK2 enzymatic activity, and co-expression mapping placed PCSK2 with intestinal peptide hormones.

    Evidence Mouse congenic strain analysis with enzymatic activity assays (Scg5); immunohistochemistry co-localization in duodenum/jejunum

    PMID:18439298 PMID:18706454

    Open questions at the time
    • Increased activity did not change alpha-MSH levels, leaving output regulation unclear
    • IHC co-localization lacks direct processing validation
  5. 2010 High

    A knockout study extended PCSK2's role beyond endocrine pancreas to gut and brain peptide processing and to intestinal physiology.

    Evidence PCSK2 knockout mouse, intestinal transit assays, refeeding measurement, enzyme immunoassay, immunoblotting

    PMID:21092739

    Open questions at the time
    • Whether processing defects act locally or systemically not separated
    • Direct substrate cleavage not shown for all altered peptides
  6. 2017 Medium

    Mutagenesis of a human coding variant tied enzyme biochemistry to potential altered substrate processing, addressing how sequence variation modulates PCSK2 function.

    Evidence In vitro transfection of human PC2 R430W constructs, enzymatic activity across pH range

    PMID:28719828

    Open questions at the time
    • No in vivo or physiological consequence demonstrated
    • Single in vitro assay
  7. 2022 Medium

    Two studies defined upstream control of PCSK2 expression: CREB transcriptional regulation in POMC neurons coupling it to energy balance, and viral suppression of PCSK2 mRNA impairing insulin maturation.

    Evidence shRNA CREB knockdown with scRNA-seq/ELISA/immunofluorescence in hypothalamus; coxsackievirus-B-TD RNA transfection in beta cells with qRT-PCR and insulin measurement

    PMID:35805082 PMID:36560784

    Open questions at the time
    • Direct CREB binding to Pcsk2 promoter not shown
    • Viral mechanism causing PCSK2 mRNA decrease not resolved
  8. 2024 Medium

    An extra-pancreatic context showed that altering PCSK2 levels redirects proglucagon processing toward glucagon, establishing that PCSK2 dosage tunes peptide product identity.

    Evidence Mouse subtotal pancreatectomy model with colonic PCSK2 expression and peptide secretion analysis (preprint)

    PMID:bio_10.1101_2024.12.23.630024

    Open questions at the time
    • Preprint, single lab
    • Direct cleavage-product analysis not fully resolved

Open questions

Synthesis pass · forward-looking unresolved questions
  • The structural basis of PCSK2 substrate specificity and how 7B2 chaperoning, pH, and expression level jointly determine which cleavage products dominate in a given cell remain unresolved.
  • No structural model of substrate selection
  • Mechanism integrating chaperone, pH, and dosage control not unified

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0140096 catalytic activity, acting on a protein 4 GO:0016787 hydrolase activity 2
Localization
GO:0031410 cytoplasmic vesicle 1
Pathway
R-HSA-1430728 Metabolism 2 R-HSA-392499 Metabolism of proteins 2
Partners
SCG5

Evidence

Reading pass · 10 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
1997 SPC2 (PCSK2) is required for the processing of proglucagon, prosomatostatin, and proinsulin in pancreatic alpha, delta, and beta cells, respectively. Mice lacking active SPC2 show severely impaired processing of these prohormones, chronic fasting hypoglycemia consistent with glucagon deficiency, and marked hyperplasia of alpha and delta cells with relative diminution of beta cells. Knockout mouse model (exon 3 deletion abrogating autoactivation and secretion), glucose tolerance testing, pancreatic islet morphology analysis Proceedings of the National Academy of Sciences of the United States of America High 9192619
1995 SPC2 (PCSK2) in neuroendocrine secretory vesicles is predominantly the full-length 64 kDa enzyme, distributed between soluble and membrane-associated fractions of secretory vesicles; the degree of membrane association is tissue-specific. Subcellular fractionation of bovine pituitary and adrenal medulla secretory vesicles, immunoreactivity analysis Journal of neurochemistry Medium 7595521
2004 SPC2 (PCSK2) uniquely cleaves dynorphin A-(1-17) to produce dynorphin A-(1-8) in betaTC-3 cells; silencing SPC2 with a delta ribozyme reduced SPC2 mRNA and protein and abolished this cleavage. Additionally, secretogranin II was identified as a potential substrate of SPC2 by differential proteomics. Delta ribozyme-mediated gene silencing in betaTC-3 stable cell lines, Northern/Western blot, dynorphin A-(1-8) measurement, differential proteomic analysis The Journal of biological chemistry Medium 14734558
2008 Overexpression of Scg5 (secretogranin V/7B2) increases PCSK2 enzymatic activity and 7B2 protein levels in mouse pituitary; despite increased PCSK2 activity, the level of the PCSK2 processing product alpha-MSH was unaltered. Mouse congenic strain analysis, DNA microarray, quantitative PCR, measurement of PCSK2 enzymatic activity and pituitary alpha-MSH levels BMC genetics Medium 18439298
2010 PCSK2 is required for normal intestinal motility and post-fast refeeding response in mice. PCSK2-null mice show delayed intestinal transit, reduced refeeding response, altered circulating levels of substance P, somatostatin, GLP-1, GLP-2, and peptide YY, and impaired processing of brain proneuropeptide Y. PCSK2 knockout mouse model, intestinal transit assay (charcoal gavage), refeeding measurement, enzyme immunoassay, immunoblotting Life sciences High 21092739
2008 PCSK2 is co-expressed with somatostatin in ~40% of SS+ cells and with substance P in ~35% of SP+ cells in mouse small intestinal duodenum and jejunum, suggesting PCSK2 participates in processing of these peptide hormones in the proximal intestine. Immunohistochemistry with co-localization analysis across intestinal regions Regulatory peptides Low 18706454
2017 A coding variant of PCSK2 (R430W) broadens the pH optimum of PC2 enzymatic activity in vitro, suggesting altered processing of PCSK2 substrates at physiological pH ranges. In vitro transfection of human PC2-encoding constructs with R430W substitution, enzymatic activity assay across pH range Diabetes research and clinical practice Medium 28719828
2022 Hypothalamic CREB transcriptionally regulates expression of Pcsk2 in arcuate nucleus POMC neurons; shRNA-mediated inhibition of CREB reduced Pcsk2 expression, decreased alpha-MSH production, and increased diet-induced body mass gain with reduced energy expenditure. Single-cell RNA sequencing, PCR, immunoblot, ELISA, immunofluorescence, shRNA lentiviral knockdown in mouse hypothalamus Cells Medium 35805082
2022 Replication of 5' terminally deleted coxsackievirus-B (CVB-TD) RNA forms in pancreatic beta cells decreases PCSK2 mRNA expression, leading to impaired insulin maturation and reduced insulin secretion. Mouse pancreatic infection model, viral RNA transfection into cultured rodent beta cells, qRT-PCR for PCSK2 mRNA, insulin plasma measurement, VP1 immunostaining co-localized with insulin content Viruses Medium 36560784
2024 Subtotal pancreatectomy increases PCSK2 expression in colonic enteroendocrine cells, shifting proglucagon processing toward glucagon production (rather than GLP-1/GLP-2), thus enabling the colon to act as an extra-pancreatic source of glucagon. Mouse subtotal pancreatectomy model, PCSK2 expression analysis in colon, measurement of glucagon and related peptide secretion bioRxivpreprint Medium bio_10.1101_2024.12.23.630024

Source papers

Stage 0 corpus · 23 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
1997 Defective prohormone processing and altered pancreatic islet morphology in mice lacking active SPC2. Proceedings of the National Academy of Sciences of the United States of America 340 9192619
2019 Serum Exosomal Long Noncoding RNA pcsk2-2:1 As A Potential Novel Diagnostic Biomarker For Gastric Cancer. OncoTargets and therapy 61 31819499
1991 Chromosomal assignments of the genes for neuroendocrine convertase PC1 (NEC1) to human 5q15-21, neuroendocrine convertase PC2 (NEC2) to human 20p11.1-11.2, and furin (mouse 7[D1-E2] region). Genomics 49 1765368
2011 Association of type 2 diabetes susceptibility genes (TCF7L2, SLC30A8, PCSK1 and PCSK2) and proinsulin conversion in a Chinese population. Molecular biology reports 46 21437630
1995 Comparison of the molecular forms of the Kex2/subtilisin-like serine proteases SPC2, SPC3, and furin in neuroendocrine secretory vesicles reveals differences in carboxyl-terminus truncation and membrane association. Journal of neurochemistry 34 7595521
2007 Association of the proprotein convertase subtilisin/kexin-type 2 (PCSK2) gene with type 2 diabetes in an African American population. Molecular genetics and metabolism 31 17618154
1995 Association of the prohormone convertase 2 gene (PCSK2) on chromosome 20 with NIDDM in Japanese subjects. Diabetes 31 7698505
2008 Expression of PCSK1 (PC1/3), PCSK2 (PC2) and PCSK3 (furin) in mouse small intestine. Regulatory peptides 29 18706454
2015 Genetic polymorphisms of PCSK2 are associated with glucose homeostasis and progression to type 2 diabetes in a Chinese population. Scientific reports 25 26607656
2004 Silencing of SPC2 expression using an engineered delta ribozyme in the mouse betaTC-3 endocrine cell line. The Journal of biological chemistry 19 14734558
1995 Proprotein convertases in amphioxus: predicted structure and expression of proteases SPC2 and SPC3. Proceedings of the National Academy of Sciences of the United States of America 19 7724604
2008 Overexpression of Scg5 increases enzymatic activity of PCSK2 and is inversely correlated with body weight in congenic mice. BMC genetics 17 18439298
2012 Effect of a common variant of the PCSK2 gene on reduced insulin secretion. Diabetologia 15 23011353
2010 PCSK2-null mice exhibit delayed intestinal motility, reduced refeeding response and altered plasma levels of several regulatory peptides. Life sciences 15 21092739
2017 Functional analysis of PCSK2 coding variants: A founder effect in the Old Order Amish population. Diabetes research and clinical practice 11 28719828
2020 PCSK2 expression in neuroendocrine tumors points to a midgut, pulmonary, or pheochromocytoma-paraganglioma origin. APMIS : acta pathologica, microbiologica, et immunologica Scandinavica 7 32794589
2009 Molecular cloning, ontogeny and tissue distribution of zebrafish (Danio rerio) prohormone convertases: pcsk1 and pcsk2. General and comparative endocrinology 5 19332069
2022 Hypothalamic CREB Regulates the Expression of Pomc-Processing Enzyme Pcsk2. Cells 4 35805082
2023 Association of common variants of TCF7L2 and PCSK2 with gestational diabetes mellitus in West Bengal, India. Nucleosides, nucleotides & nucleic acids 3 37610142
2024 Spc2 modulates substrate- and cleavage site-selection in the yeast signal peptidase complex. The Journal of cell biology 2 39565596
2022 Replication Activities of Major 5' Terminally Deleted Group-B Coxsackievirus RNA Forms Decrease PCSK2 mRNA Expression Impairing Insulin Maturation in Pancreatic Beta Cells. Viruses 2 36560784
2024 PCSK2 can be Useful in a Panel Approach to Distinguish Foregut and Midgut Neuroendocrine Tumors. International journal of surgical pathology 1 39034588
2023 Susceptibility of PCSK2 Polymorphism to Hirschsprung Disease in Southern Chinese Children. Clinical and experimental gastroenterology 0 37215434

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