Menin represses GLP1R - the receptor a whole class of diabetes drugs exists to switch on
also called menin GLP1R · GLP-1 receptor menin · menin PRMT5 GLP1R
Menin keeps the gene for the GLP-1 receptor turned down. That receptor is the target of the biggest class of diabetes and weight drugs there is, so blocking menin turns up the very thing those drugs try to stimulate.
The same thing, for a scientist
Menin, with PRMT5, suppresses GLP1R transcript levels in beta cells, and additionally suppresses GLP1-induced, PKA-mediated phosphorylation of FOXO1 (S253) and CREB, thereby raising FOXO1 levels and damping CREB target genes; a small-molecule menin inhibitor reverses that suppression, and ex vivo treatment of **both mouse and human** pancreatic islets with a menin inhibitor raises Ki67 [E1]. The axis is corroborated in vivo and in human cells from the opposite direction: normal-sized islets of Men1(+/-) mice show increased GLP-1R sufficient to be imaged with 68Ga-exendin-4 PET [E2], and MEN1 patient-derived iPSC beta-like cells hypersecrete insulin in a GLP-1R- and PI3K-dependent manner, with GLP-1R blockade reversing it [E3]. So menin sits directly upstream of the incretin receptor in the beta cell, in mouse and in human material, and pharmacological menin blockade de-represses it.
Why this is a different order of finding from 'menin is a tumour suppressor'
GLP1R is not an obscure menin target. It is the receptor agonised by exenatide, liraglutide, semaglutide and tirzepatide - a therapeutic class prescribed to tens of millions of people, precisely to expand and protect beta-cell function. A drug that de-represses GLP1R in the beta cell is, mechanistically, pushing on the same node from one step upstream. The graph currently frames every normal-tissue consequence of menin blockade as a hazard; this one is the mechanism of a licensed therapeutic strategy.
What the paper reports, in order1 deeper
- Menin and PRMT5 suppress GLP1R transcript levels 1.
- A GLP1R agonist induces PKA-mediated FOXO1 S253 phosphorylation; menin suppresses that, and suppresses PKA-mediated CREB phosphorylation, likely through a protein arginine methyltransferase 1.
- The consequence is higher FOXO1 protein and damped CREB target genes - i.e. menin closes the incretin signalling arm at two levels, receptor abundance and downstream phosphorylation 1.
- A small-molecule menin inhibitor reverses the suppression of both FOXO1 and CREB phosphorylation 1.
- Ex vivo menin inhibition raises Ki67 in mouse and human pancreatic islets 1.
Provenance note on the human-islet Ki67 claim
The statement that a menin inhibitor raises Ki67 in human islets traces to this paper 1, not to the Pbk paper it is sometimes attributed to. In the Pbk paper the human-islet Ki67 mRNA change reaches significance at one concentration only (see mechanism-menin-jund-hdac3-pbk-axis-in-beta-cells). Both are ex vivo, both use tool compounds, and neither uses a clinical menin inhibitor.
Corroboration from the genetic side, including human cells
- In vivo imaging. Men1(+/-) mouse islets of normal size already over-express GLP-1R, enough that 68Ga-exendin-4 PET detects them - GLP-1R up-regulation is an early, pre-tumour consequence of reduced menin, not a late tumour marker 2.
- Human iPSC. Beta-like cells differentiated from MEN1-patient iPSCs hypersecrete insulin with raised PC1/3, GLP-1, GLP-1R and PI3K/AKT signalling; blocking GLP-1R or PI3K reduces both the insulin-positive fraction and the hypersecretion 3. This is the axis operating in human MEN1-mutant cells.
The other edge of it
GLP-1R up-regulation in a menin-reduced beta cell is also the tumour-imaging signal in MEN1 2 and the hypersecretion mechanism in MEN1 patient cells 3. The same de-repression that would be therapeutic in diabetes is, in the MEN1 pancreas, part of the pre-neoplastic phenotype. A child on a menin inhibitor is receiving a pharmacological version of that de-repression; whether the endpoint is improved insulin secretion or the first step of the MEN1 islet trajectory is not determined by any of these three papers.
| target gene | GLP1R |
|---|---|
| direction | menin (with PRMT5) represses; menin inhibition de-represses |
| therapeutic context | GLP1R is the target of the GLP-1 receptor agonist drug class |
downstream
[ "PKA-mediated FOXO1 S253 phosphorylation", "CREB phosphorylation", "FOXO1 protein level", "CREB target genes" ]
species
[ "mouse", "human (ex vivo islets, iPSC-derived beta-like cells)" ]
- De-repressing GLP1R in a leukaemia patient means an unmonitored change in insulin secretion in someone receiving corticosteroids, asparaginase and total parenteral nutrition - all of which move glucose hard in the other direction.
- The same de-repression is the imaging signature of pre-neoplastic MEN1 islets, so the beneficial and the pre-tumour readouts are the same measurement.
- If a treated child is later given a GLP-1 receptor agonist, the two act on the same node, and no interaction data exist.
- Do revumenib-treated patients show altered fasting GLP-1, insulin or C-peptide? No trial and neither label reports any of these.
- Is GLP1R de-repression dose-proportional to menin pocket occupancy, and could a circulating GLP-1R-dependent analyte serve as a peripheral pharmacodynamic marker of endocrine target engagement?
- In a child, does GLP1R de-repression in the intestine and islet interact with the appetite and weight problems that already follow leukaemia treatment?
- E1moderate confidence 3 of 5: One strong study, or several smaller consistent ones.paper
Menin and PRMT5 suppress GLP1R transcript and PKA-mediated FOXO1/CREB phosphorylation; a menin inhibitor reverses this and raises Ki67 in mouse and human islets ex vivo.
Menin and PRMT5 suppress GLP1 receptor transcript and PKA-mediated phosphorylation of FOXO1 and CREB. · Muhammad AB, Xing B, Liu C, Naji A, et al. · American Journal of Physiology - Endocrinology and Metabolism 2017What this evidence cannot show
Largely cell-line and ex-vivo islet work; the menin inhibitor is a tool compound and the abstract does not name it or state concentrations; the PRMT5 arm is inferential ('likely through a protein arginine methyltransferase'); no in-vivo glucose endpoint in this paper.
Evidence that argues against this (1)
- The same GLP-1R de-repression is the basis of exendin-4 PET detection of pre-neoplastic Men1(+/-) islets, i.e. it is a marker of the MEN1 lesion, not only of healthy compensation. Monazzam A et al. 2018
- E2moderate confidence 3 of 5: One strong study, or several smaller consistent ones.paper
Normal-sized islets in Men1 heterozygous mice over-express GLP-1R, detectably by 68Ga-exendin-4 PET.
Increased Expression of GLP-1R in Proliferating Islets of Men1 Mice is Detectable by [68Ga]Ga-DO3A-VS-Cys40-Exendin-4 /PET. · Monazzam A, Lau J, Velikyan I, Li SC, Razmara M, Rosenstrom U, et al. · Scientific Reports 2018What this evidence cannot show
Heterozygous germline model, not pharmacological inhibition; PET is a whole-pancreas readout and the paper's framing is diagnostic, aimed at early lesion detection.
Evidence that argues against this (1)
- GLP-1R is also up-regulated in healthy compensatory beta-cell states, so its elevation is not specific to a pre-neoplastic islet. Muhammad AB et al. 2017
- E3moderate confidence 3 of 5: One strong study, or several smaller consistent ones.paper
MEN1 patient-derived iPSC beta-like cells hypersecrete insulin via GLP-1R and PI3K, reversible by blocking either.
Modeling MEN1 with Patient-Origin iPSCs Reveals GLP-1R Mediated Hypersecretion of Insulin. · Cheng Z, Guo D, Ruzi A, Pan T, You K, Chen Y, et al. · Cells 2022What this evidence cannot show
iPSC-derived cells are immature relative to adult human beta cells; the comparison is patient-origin versus control lines rather than isogenic; tumour formation on transplant was observed only for the beta-like stage.
Evidence that argues against this (1)
- This is germline MEN1 mutation in every cell from the pluripotent stage, the maximal-exposure end of the spectrum, and says nothing directly about partial pharmacological occupancy. Syndax Pharmaceuticals et al. 2026
Menin, with PRMT5, represses GLP1R transcript and PKA-mediated FOXO1/CREB phosphorylation in beta cells
Provides the receptor-level mechanism for the in-vivo glucose benefit, and the human-islet Ki67 result the in-vivo paper is often miscredited with
- ← co-occurs withMenin inhibition in the gut, not the islet: MI-463 raises GLP-1 from intestinal L cells
Two anatomically separate arms of the same pharmacology: more GLP-1 released from gut L cells, arriving at a beta cell whose GLP1R menin has stopped repressing
- ← depends onWhy endocrine tumours do not carry KRAS mutations: menin blocks the proliferative arm of RAS
The reported GLP1-agonist x menin-inhibitor proliferative synergy is amplified by menin's own repression of GLP1R: the drug supplies the receptor arm of its own combination
- ← part ofThe same drug target, pursued for benefit: menin inhibition is a diabetes strategy in the literature
The GLP1R arm, and the source of the human-islet Ki67 result
the menin-PRMT5 complex this graph already holds