9wv1
Human TIM22 complex wtih substrate GGC1-sfGFP
Structural highlights
DiseaseTIM22_HUMAN The disease is caused by variants affecting the gene represented in this entry. FunctionTIM22_HUMAN Essential core component of the TIM22 complex, a complex that mediates the import and insertion of multi-pass transmembrane proteins into the mitochondrial inner membrane. In the TIM22 complex, it constitutes the voltage-activated and signal-gated channel. Forms a twin-pore translocase that uses the membrane potential as external driving force in 2 voltage-dependent steps (By similarity).[UniProtKB:Q12328] Publication Abstract from PubMedMetabolite carriers that control essential metabolite transport are imported into mitochondria through the TOM and TIM22 complexes. How TOM and TIM22 coordinate in human mitochondria has remained largely unknown. Here we show that human TOM and TIM22 assemble into a supercomplex that seamlessly couples carrier translocation across the outer and inner membranes, unlike in yeast where the two complexes appear to function separately. Cryo-electron microscopy structures of the human TOM-TIM22 supercomplex reveal unpaired carrier transmembrane segments traversing the TOM channel along a hydrophobic path and exiting through an unexpected lateral groove outside the channel. The membrane-bound small Tim subunits provide the substrate entry site for TIM22, while a membrane-exposed groove of TIM22 serves as the exit for carrier insertion into the inner membrane. These findings provide insights into the human carrier translocation pathway at molecular resolution and establish the TOM-TIM22 supercomplex as a central organizing unit of mitochondrial carrier import. Direct coupling of human TOM and TIM22 complexes drives mitochondrial carrier import.,Liu X, Cai H, Wang H, Zhou X, Zhang Y, Liu S, Zhu J, Li L Nat Struct Mol Biol. 2026 Jul 23. doi: 10.1038/s41594-026-01849-w. PMID:42493623[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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