TMEM11

TMEM11 is a mitochondrial membrane protein that shapes mitochondrial network morphology and constrains receptor-mediated mitophagy (PMID:21274005, PMID:36795401). It localizes to the outer mitochondrial membrane (PMID:39149412) and regulates network morphology through a pathway genetically separable from the canonical DRP1/Mitofusin fission–fusion machinery, since loss of its Drosophila ortholog PMI produces a condensed network independent of drp1 and mfn (PMID:21274005). At the mitophagy interface, TMEM11 forms a complex with the outer-membrane receptor proteins BNIP3 and BNIP3L and co-enriches at sites of mitophagosome formation; its loss increases the number of mitophagy sites and hyperactivates BNIP3/BNIP3L-driven mitophagy under both normoxia and hypoxia-mimetic conditions, establishing TMEM11 as a spatial restrictor of mitophagosome nucleation (PMID:36795401). This BNIP3-suppressing activity has disease relevance: in bladder cancer cells TMEM11 suppresses BNIP3 expression and impairs mitophagy flux to stabilize mitochondria and promote cisplatin resistance (PMID:41570932). Independent of its membrane role, TMEM11 interacts with the m7G methyltransferase METTL1 to enhance m7G methylation of Atf5 mRNA, raising ATF5 protein and driving an ATF5–INCA1 axis that suppresses cardiomyocyte proliferation (PMID:37286744).

1. 2011 High

   Established that TMEM11/PMI controls mitochondrial network shape through a pathway distinct from the known fission–fusion machinery, defining a novel morphogenesis regulator.

   Evidence Genetic loss-of-function and reciprocal epistasis with drp1 and mfn plus endogenous localization in Drosophila

   PMID:21274005

   Open questions at the time

   • Molecular activity producing the condensed-network phenotype not defined
   • Inner-membrane localization in Drosophila later contradicted by outer-membrane reports in other species
   • No direct partners identified at this stage
2. 2023 High

   Answered how TMEM11 intersects with selective mitophagy, showing it physically partners with BNIP3/BNIP3L and spatially limits where mitophagosomes form.

   Evidence Reciprocal Co-IP, fluorescence co-localization at mitophagy sites, and quantitative mitophagy assays in KO cells under normoxia and hypoxia-mimetic conditions

   PMID:36795401

   Open questions at the time

   • Structural basis for restricting site number unknown
   • Relationship between morphology role and mitophagy site control not resolved
   • Whether the BNIP3/BNIP3L complex requires additional subunits unaddressed
3. 2023 High

   Revealed an unexpected non-morphology function in which TMEM11 acts through METTL1-dependent mRNA modification to control a proliferation-suppressing transcriptional axis.

   Evidence Co-IP of TMEM11–METTL1, m7G methylation assay of Atf5 mRNA, and in vitro/in vivo loss- and gain-of-function in cardiomyocytes with ATF5–INCA1 readouts

   PMID:37286744

   Open questions at the time

   • How an outer-membrane protein engages a methyltransferase acting on mRNA is mechanistically unexplained
   • Whether this links to TMEM11's mitochondrial functions unknown
   • Direct binding interface with METTL1 not mapped
4. 2024 Medium

   Resolved the localization discrepancy by placing TMEM11 at the outer mitochondrial membrane, consistent with its mitophagy-receptor partnerships.

   Evidence Fluorescent fusion live imaging and biochemical membrane fractionation of both zebrafish Tmem11 splice variants

   PMID:39149412

   Open questions at the time

   • Single lab, ortholog-based
   • Topology and membrane-spanning architecture not defined
   • Does not reconcile with earlier Drosophila inner-membrane report mechanistically
5. 2026 Medium

   Extended the BNIP3-restricting function to a disease context, showing TMEM11 suppresses mitophagy to drive chemoresistance.

   Evidence TMEM11 knockdown with mitophagy flux and apoptosis assays, BNIP3 expression analysis, and in vivo xenograft cisplatin sensitization in bladder cancer

   PMID:41570932

   Open questions at the time

   • Single lab
   • Mechanism of BNIP3 expression suppression versus the earlier spatial-restriction model not reconciled
   • Curcumin as TMEM11 inhibitor only by docking, not validated biochemically

• The molecular activity that lets TMEM11 both shape mitochondrial networks and gate mitophagosome formation, and how this reconciles with its METTL1/m7G role, remains undefined.
• No structural or enzymatic activity assigned to TMEM11
• Unclear whether morphology, mitophagy, and m7G functions share a common mechanism
• No reconciliation of suppressing BNIP3 expression versus restricting BNIP3 site number