mitochondrial multifunctional assembly

cellstructuremech:mitochondrial_multifunctional_assembly · Other · Multiprotein complex · Proposed

A biochemically isolatable protein-lipid assembly of the mitochondrial inner membrane characterized in Saccharomyces cerevisiae. MIMAS brings together metabolite carriers, dehydrogenases, respiratory-chain biogenesis factors and phospholipid enzymes, with stability dependent on phosphatidylethanolamine production. [DOI:10.1016/j.celrep.2024.113772]

Synonyms: MIMAS

Part of: mitochondrial inner membrane (GO:0005743)

UniProt location names: UniProt Consortium, CC BY 4.0. Reference label and route sources.

Components

Component	Type	Part of / acts on	Grounding	Genes	Essential	Role
ADP/ATP carrier protein, eukaryotic type	Protein	part of	`InterPro:IPR002113`	AAC2, PET9	UNKNOWN	Metabolite carrier represented by the MIMAS-associated pool of Aac2. `DOI:10.1016/j.celrep.2024.113772` Figures 1B and 2G-J: complexome migration, enrichment in intact Psd1-isolated MIMAS, and Nde1-AAC crosslinking support membership; not all cellular AAC is in MIMAS.
Mitochondrial Respiratory Supercomplex Factor 1	Protein	part of	`InterPro:IPR050355`	RCF1	UNKNOWN	Respiratory assembly factor with MIMAS-associated and respiratory-chain pools. `DOI:10.1016/j.celrep.2024.113772` Figures 1A-B, 2F and 4G: Rcf1 co-migrates and co-isolates with MIMAS. R67A reduces its MIMAS association, whereas Q61A/Q71A increases it, in the tested rcf1/rcf2 deletion background. This does not establish fixed occupancy.
Phosphatidylserine decarboxylase, eukaryotic type 1	Protein	part of	`InterPro:IPR033661`	PSD1	UNKNOWN	Phosphatidylethanolamine-producing constituent used to isolate intact MIMAS. `DOI:10.1016/j.celrep.2024.113772` Figures 2E-H and 3F-G: Psd1 is incorporated into MIMAS. Active Psd1, but not S463A, restores MIMAS integrity in psd1-null cells, although S463A can join MIMAS in wild-type mitochondria. Catalytic competence and physical incorporation are distinct; complete assembly essentiality is not assigned from destabilization.
external mitochondrial NADH dehydrogenase	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	NDE1	UNKNOWN	Intermembrane-space-facing dehydrogenase represented by the MIMAS-associated Nde1 pool. `DOI:10.1016/j.celrep.2024.113772` Figure 2A-C,F-G,I-J: Nde1 co-migrates and co-isolates with MIMAS; crosslinking in intact mitochondria followed by denaturing affinity isolation supports proximity to AAC. The matrix-facing Ndi1 has a different profile.
Tafazzin	Protein	part of	`InterPro:IPR000872`	TAZ1	UNKNOWN	Phospholipid-remodeling enzyme with a MIMAS-associated population. `DOI:10.1016/j.celrep.2024.113772` Figure 2D-F: Taz1 migrates in the MIMAS range and is recovered with Psd1. Its membership does not prove that cardiolipin remodeling is locally coupled to transport or respiratory-chain assembly.

Canonical examples

NCBITaxon:4932 Saccharomyces cerevisiae — The primary study uses YPH499- or W303-1A-derived strains and isolated mitochondria. Culture conditions vary by experiment. Methods identify a Neurospora crassa AAC construct for import assays, despite Figure 1F naming Aac2; this heterologous precursor does not establish a second canonical organism. Endogenous yeast AAC membership has separate complexome and biochemical support. [DOI:10.1016/j.celrep.2024.113772]

Functions

platform for respiratory-chain subunit biogenesis — MIMAS groups respiratory biogenesis factors and transiently accommodates imported Cox13. Its role as a platform preceding incorporation into complex IV is an interpretation of import/chase and Rcf1-association experiments, not direct tracking of transfer between complexes or an obligatory route for all respiratory subunits.
- DOI:10.1016/j.celrep.2024.113772 Figure 4D-G: precursor import/chase distinguishes transient Cox13 association from mature respiratory complexes. Rcf1 point mutants shift its distribution. The source presents broader metabolic integration as a model.

Mechanism graphs

Psd1 activity supports MIMAS integrity (ASSEMBLY)

Subject	Predicate	Object	Evidence
Phosphatidylserine decarboxylase, eukaryotic type 1	catalyzes	Psd1-dependent phosphatidylethanolamine production	`DOI:10.1016/j.celrep.2024.113772` Results on phospholipid biosynthesis and Figure 3 distinguish active Psd1 from its catalytically inactive S463A variant.
Psd1-dependent phosphatidylethanolamine production	supports	MIMAS integrity	`DOI:10.1016/j.celrep.2024.113772` Figure 3B-G: psd1 deletion destabilizes MIMAS, whereas crd1 deletion does not show the same effect. Active Psd1 rescues the psd1-null defect, while S463A does not despite incorporation in wild-type mitochondria. PE dependence is the authors' mechanistic inference from these experiments, not direct measurement of a lipid-protein contact.

Discussions

CURATION_TODO (RESOLVED): Distinguish MIMAS from other mitochondrial assemblies. Similar mitochondrial-complex names do not establish equivalent identity.
CURATION_TODO (OPEN): Resolve complete membership and architecture. The first record represents experimentally supported classes, not an exhaustive stoichiometry.
CURATION_TODO (RESOLVED): Keep transient clients and neighboring complexes separate. A transient assembly intermediate is not mature constituent membership.
CURATION_TODO (OPEN): Resolve external dehydrogenase grounding and studied-strain examples. Reference-proteome annotations do not identify every experimentally used allele.
CURATION_TODO (OPEN): Test local metabolic coupling and lipid organization. Proximity and enzyme membership do not establish metabolite channeling.

Datasets

Psd1 affinity-isolation and native-gel MIMAS proteomics (PXD047946) · PRIDE · PROTEOMICS
Organism: Saccharomyces cerevisiae
Native accession, title, taxon 4932 and DOI verified. The repository reports a PARTIAL submission and PMID zero, which is a placeholder and is not imported. Enrichment identifies Psd1 interactors, not exclusively invariant MIMAS constituents. No spectra, protein table or repository prose is redistributed.

Evidence

DOI:10.1016/j.celrep.2024.113772 Horten et al.; PMID:38393949. Current PMC11010658.1 identity and JATS checksum verified. Results, Discussion, limitations, strain, isolation, interaction and import Methods inspected. Native Figures 2-4 visually inspected with media checksum verification. The CC BY-NC-ND 4.0 figures are not hosted.
DOI:10.1002/pro.70653 PMID:42178653; current PMC13240547.1 identity and JATS checksum verified. Section 1.1 supplies expanded-name and boundary context, while retaining metabolic integration and local lipid organization as hypotheses. It does not establish a broader taxonomic distribution.

Curation history

2026-10-04T20:20:25Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-10-04T20:22:27Z codex · CURATED_RECORD — Added five bounded constituent classes, verified family mappings and mitochondrial hierarchy, yeast example, PRIDE link, respiratory-biogenesis function, short PE-dependent integrity mechanism, and explicit client, strain, stoichiometry and image-license limits.
2026-10-04T20:26:45Z codex · REFINED_FUNCTION_SCOPE — Distinguished transient Cox13 association observed in import/chase assays from the proposed transfer route into mature complex IV before PR submission.

Source: data/structures/other/mitochondrial_multifunctional_assembly.yaml