EMC10

EMC10 encodes two functionally distinct isoforms — a secreted form (scEMC10) and a membrane-bound form (mEMC10) — that exert opposing or tissue-specific effects on metabolism, ER stress, and cell physiology. scEMC10 acts as a circulating inhibitor of energy expenditure by binding the catalytic subunit of PKA and suppressing CREB-dependent thermogenesis in adipocytes (PMID:36443308), inhibits muscle glucose uptake by suppressing AMPK activation, insulin signaling, and GLUT4 translocation (PMID:40441535), and promotes hepatic ER stress through the PERK–eIF2α–ATF4 axis, whereas mEMC10 suppresses this same pathway and protects against steatosis (PMID:38599383). mEMC10 is also required in spermatozoa for Na/K-ATPase (ATP1B3) expression and sodium homeostasis, maintaining sperm motility and capacitation (PMID:29659949, PMID:36077468). In the brain, EMC10 (Mirta22) inhibits neuronal maturation and synaptic plasticity, and its upregulation mediates behavioral deficits in the Df(16)A mouse model of 22q11.2 deletion syndrome-associated schizophrenia (PMID:28696314).

1. 2009 Medium

   Establishing that EMC10 is a secreted, glucose-regulated peptide from pancreatic beta cells provided the first indication that this gene product functions as a circulating factor rather than solely an ER membrane component.

   Evidence Glucose stimulation of MIN6 cells and isolated islets with Northern blot and ELISA detection of secreted protein

   PMID:19570817

   Open questions at the time

   • Single-lab observation without independent confirmation
   • Downstream targets of secreted EMC10 in beta cells uncharacterized
   • Physiological role of glucose-regulated secretion unclear
2. 2017 High

   Two independent studies revealed EMC10's roles outside the ER membrane complex: one showed it promotes post-infarction angiogenesis through p38 MAPK–MK2 signaling in endothelial cells (sourced from bone marrow monocytes/macrophages), and another demonstrated that brain-expressed Mirta22/EMC10 inhibits neuronal maturation and that its genetic reduction rescues schizophrenia-related behavioral and synaptic deficits in the 22q11.2 deletion mouse model.

   Evidence Emc10-KO and bone marrow chimera mice with infarcted heart explant assays and signaling analysis [PMID:28931551]; genetic epistasis of Mirta22 loss-of-function in Df(16)A mice with behavioral and synaptic plasticity readouts [PMID:28696314]

   PMID:28696314 PMID:28931551

   Open questions at the time

   • Direct molecular target of EMC10 in endothelial cells not identified
   • Mechanism by which EMC10 inhibits neuronal maturation at the molecular level remains unclear
   • Relationship between angiogenic and neuronal functions not addressed
3. 2018 High

   EMC10 was shown to be required for Na/K-ATPase activity in spermatozoa, linking it to ion homeostasis, motility, capacitation, and male fertility, and establishing its first cell-autonomous membrane-associated function.

   Evidence Emc10-KO mouse spermatozoa with Na/K-ATPase activity assays, intracellular Na+ measurements, phosphorylation cascades, and ICSI rescue

   PMID:29659949

   Open questions at the time

   • Whether EMC10 acts as a chaperone for Na/K-ATPase assembly or has a direct structural role was unresolved
   • Isoform specificity not yet determined
4. 2022 High

   Isoform-specific rescue experiments resolved the duality of EMC10: mEMC10 (not scEMC10) supports sperm Na/K-ATPase β3 subunit expression and motility, while scEMC10 was independently shown to act as a circulating inhibitor of thermogenesis by directly binding the PKA catalytic subunit and suppressing CREB phosphorylation.

   Evidence Intra-testis mEMC10 overexpression rescue in KO mice with negative scEMC10 control [PMID:36077468]; co-IP of scEMC10 with PKA catalytic subunit, KO/OE metabolic phenotyping, and neutralizing antibody in adipocytes [PMID:36443308]

   PMID:36077468 PMID:36443308

   Open questions at the time

   • Structural basis of scEMC10–PKA interaction unknown
   • How mEMC10 promotes ATP1B3 expression mechanistically not defined
   • Whether scEMC10-PKA inhibition operates in tissues beyond adipocytes was untested
5. 2024 High

   The opposing roles of EMC10 isoforms were extended to hepatic ER stress: scEMC10 promotes while mEMC10 suppresses the PERK–eIF2α–ATF4 pathway, establishing isoform-specific regulation of the unfolded protein response as a mechanism underlying steatosis modulation.

   Evidence Emc10-KO mice, isoform-specific hepatic overexpression, tunicamycin and MCD diet stress models, scEMC10 neutralizing antibody, HepG2 cell PERK pathway analysis

   PMID:38599383

   Open questions at the time

   • Direct molecular target of mEMC10 in ER stress suppression not identified
   • Whether mEMC10 acts through its role in the EMC complex or independently is unclear
   • Relevance to human NAFLD/NASH not yet established
6. 2025 High

   scEMC10 was shown to suppress muscle glucose uptake by inhibiting GLUT4 expression and translocation through suppression of AMPK and insulin signaling, broadening its role as a systemic metabolic inhibitor beyond thermogenesis.

   Evidence Emc10-KO mice, recombinant scEMC10 in myoblasts, neutralizing antibody phenocopying KO, GLUT4 translocation and AMPK/insulin pathway analysis

   PMID:40441535

   Open questions at the time

   • Whether scEMC10 inhibits muscle glucose uptake through the same PKA-binding mechanism identified in adipocytes is untested
   • Receptor or uptake mechanism for scEMC10 entry into muscle cells unknown

• Key unresolved questions include: the receptor or uptake mechanism by which scEMC10 enters target cells, the structural basis of scEMC10–PKA interaction, whether mEMC10 functions as part of the canonical ER membrane protein complex or independently, and the molecular mechanism by which EMC10 inhibits neuronal maturation.
• No receptor identified for scEMC10 cellular entry
• No structural model for scEMC10–PKA complex
• Relationship between EMC10's role in the EMC complex and its isoform-specific signaling functions unexplored