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SCIENCE

The Claim

LETM1 is a proton-coupled mitochondrial calcium transport pathway that complements the mitochondrial calcium uniporter (MCU) and the sodium/calcium/lithium exchanger (NCLX) in controlling mitochondrial Ca2+ dynamics.

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The Short Version

The claim is well supported in its narrower form. Current evidence indicates LETM1 can mediate proton-coupled mitochondrial Ca2+ transport and contributes to Ca2+ handling alongside MCU and NCLX. The main caveat is that newer literature often assigns the primary bulk Ca2+/H+ exchanger role in mammals to TMBIM5, making LETM1 better described as complementary or regulatory than dominant.

Caveats

  • Do not read this as meaning LETM1 is the main mitochondrial Ca2+/H+ exchanger in mammals; recent studies often assign that role to TMBIM5.
  • The term "pathway" is broader than the evidence; most data concern LETM1 as a transporter/protein with context-dependent effects, not a universally dominant route.
  • Some mechanistic details remain debated across species, tissues, and experimental systems, so the strength of LETM1’s contribution is not uniform in all mitochondria.

The Receipts

  1. Letm1, the mitochondrial Ca2+/H+ antiporter, is essential for normal glucose metabolism and mitochondrial bioenergetics

    PNAS

  2. Functional reconstitution of the mitochondrial Ca2+/H+ antiporter Letm1

    The Journal of General Physiology

  3. PINK1-mediated phosphorylation of LETM1 regulates mitochondrial calcium transport and protects neurons from mitochondrial defects

    Nature Communications

  4. Functional reconstitution of the mitochondrial Ca2+/H+ antiporter Letm1

    PMC (NIH)

  5. Calcium Signalling: Fishing Out Molecules of Mitochondrial Calcium Transport

    PMC

  6. The Pathophysiology of LETM1

    Proceedings of the National Academy of Sciences (PMC/NIH)

  7. Leucine zipper-EF-hand containing transmembrane protein 1 (LETM1) forms a Ca2+/H+ antiporter via oligomerization

    Nature Scientific Reports

  8. LETM1: A Single Entity With Diverse Impact on Mitochondrial Biology and Disease

    Frontiers in Physiology

  9. Functional reconstitution of the mitochondrial Ca2+/H+ antiporter Letm1

    Harvard University DASH repository

  10. The Ins and Outs of Mitochondrial Calcium

    Circulation Research

+ 11 more sources — see the full list on Lenz

Filed Under

LETM1Mitochondrial CalciumMitochondrial Calcium UniporterNCLX

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