SAM complex

GO:0001401 · Other · Multiprotein complex · Proposed

A large complex of the mitochondrial outer membrane that mediates sorting of some imported proteins to the outer membrane and their assembly in the membrane; functions after import of incoming proteins by the mitochondrial outer membrane translocase complex. [GO:0001401]

Synonyms: mitochondrial sorting and assembly machinery complex; TOB complex

Part of: mitochondrial outer membrane (GO:0005741)

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

Taxonomic distribution

NCBITaxon:4932 Saccharomyces cerevisiae — COMMON: Budding-yeast mitochondria contain SAM, a sorting and assembly machinery that acts after TOM in the outer-membrane protein biogenesis pathway. [DOI:10.1038/nature01753]

Canonical examples

NCBITaxon:4932 Saccharomyces cerevisiae — Yeast model in which the mitochondrial outer membrane sorting and assembly machinery was distinguished from TOM and Mas37 was shown to be a SAM-complex constituent. [DOI:10.1038/nature01753]

Functions

protein insertion into mitochondrial outer membrane GO:0045040 — The SAM complex acts after TOM to sort and assemble a subset of imported proteins into the mitochondrial outer membrane.
- GO:0001401 GO:0001401 defines SAM as the mitochondrial outer-membrane machinery that sorts some imported proteins and assembles them into the membrane after TOM import.
- GO:0045040 GO:0045040 defines insertion of proteins into the mitochondrial outer membrane by large outer-membrane translocase complexes.
- DOI:10.1038/nature01753 Wiedemann et al. 2003 separated the SAM outer-membrane sorting and assembly step from the upstream TOM translocase step.

Mechanism graphs

SAM assembles imported outer-membrane precursors after TOM (FUNCTION)

In the mitochondrial outer membrane, the SAM complex acts after TOM to sort and assemble imported outer-membrane precursor proteins.

Subject	Predicate	Object	Evidence
SAM complex	is part of	mitochondrial outer membrane	`GO:0001401` GO:0001401 defines SAM as a large complex of the mitochondrial outer membrane.
mitochondrial outer membrane translocase complex	transfers precursors to	SAM complex	`GO:0001401` GO:0001401 defines SAM as functioning after TOM in the sorting and assembly of imported outer-membrane proteins. `DOI:10.1038/nature01753` Wiedemann et al. 2003 separated SAM-mediated outer-membrane sorting and assembly from the TOM import step.
SAM complex	mediates	protein insertion into mitochondrial outer membrane	`GO:0045040` GO:0045040 grounds the protein-insertion process that places imported proteins into the mitochondrial outer membrane.

Discussions

CURATION_TODO (OPEN): Resolve exact source-neutral component groundings for bona fide SAM constituents before adding Sam subunit rows. GO exactly grounds the SAM complex itself, but this first record does not assert InterPro, Pfam, NCBIfam, or UniProt family CURIEs for Sam50, Sam35/Tob38, Sam37/Mas37, Mdm10, or partner factors until their source-neutral family boundaries are verified.

Evidence

GO:0001401 Gene Ontology cellular-component term for the SAM complex.
GO:0098799 Gene Ontology cellular-component parent term for outer mitochondrial membrane protein complexes.
GO:0005741 Gene Ontology cellular-component term for the mitochondrial outer membrane that carries SAM.
GO:0005742 Gene Ontology cellular-component term for the upstream TOM complex named in the GO:0001401 definition.
GO:0045040 Gene Ontology biological-process term for protein insertion into the mitochondrial outer membrane.
DOI:10.1038/nature01753 Wiedemann et al. 2003, Machinery for protein sorting and assembly in the mitochondrial outer membrane, Nature.

Curation history

2026-09-18T15:12:55Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-18T15:14:22Z codex · EXPANDED_RECORD — Added GO synonymy, outer-mitochondrial-membrane protein-complex parentage, mitochondrial-outer-membrane parthood, Saccharomyces scope, TOM-SAM outer-membrane protein-insertion function evidence, a nonmechanistic TOM-to-SAM graph, and a SAM subunit-boundary TODO.
2026-09-18T15:18:48Z codex · NARROW_FUNCTION_GROUNDING — Replaced a newer QuickGO TOM-SAM pathway grounding with the OAK-visible GO:0045040 protein insertion into mitochondrial outer membrane term while preserving the SAM-specific TOM handoff in notes.
2026-09-18T15:19:23Z codex · NARROW_EVIDENCE_SCOPE — Removed a stale beta-barrel-only phrase from the TOM-to-SAM edge after switching to the broader GO:0045040 outer-membrane protein-insertion grounding.
2026-09-18T15:28:16Z codex · ALIGN_HISTORY_WORDING — Updated the initial expansion summary to describe the final GO:0045040 outer-membrane protein-insertion grounding.
2026-09-18T15:34:05Z codex · ADDRESS_REVIEW — Resolved #1161 and #1162 by removing an unattached review citation and rephrasing the SAM-to-protein-insertion graph edge so the complex mediates a process rather than assembling a process node.
2026-09-18T15:39:55Z codex · ALIGN_REVIEW_HISTORY — Removed #1160 from the review-fix curation summary after re-checking that it was not an active PR #1159 defect.

Source: data/structures/other/sam_complex.yaml