PAM complex, Tim23 associated import motor

GO:0001405 · Other · Multiprotein complex · Proposed

A mitochondrial matrix-side protein complex associated with the TIM23 inner-membrane translocase that uses ATPase motor activity to drive protein import into the mitochondrial matrix. [GO:0001405]

Synonyms: mitochondrial import motor; PAM complex; pre-sequence translocase-associated import motor; presequence translocase-associated import motor

Part of: TIM23 mitochondrial import inner membrane translocase complex (GO:0005744); mitochondrial matrix (GO:0005759)

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 the PAM import motor that associates with TIM23 on the matrix side of the inner membrane during preprotein import. [DOI:10.1083/jcb.200308004]

Canonical examples

NCBITaxon:4932 Saccharomyces cerevisiae — Budding-yeast model for defining a J-protein component of the TIM23-associated PAM import motor. [DOI:10.1093/emboj/cdg485]

Functions

protein import into mitochondrial matrix GO:0030150 — PAM powers the matrix-side step of TIM23-dependent preprotein import into the mitochondrial matrix.
- GO:0001405 GO:0001405 defines PAM as a TIM23-associated matrix-side import motor with ATPase activity that drives protein import into the mitochondrial matrix.
- GO:0030150 GO:0030150 denotes protein import into the mitochondrial matrix.
- DOI:10.1016/j.cell.2009.08.005 Chacinska et al. 2009 reviewed the TIM23-PAM presequence pathway for mitochondrial matrix import.

Mechanism graphs

PAM powers TIM23-dependent matrix import (FUNCTION)

PAM associates with TIM23 at the mitochondrial matrix side of the inner membrane and drives preprotein import into the matrix.

Subject	Predicate	Object	Evidence
PAM complex, Tim23 associated import motor	is part of	TIM23 mitochondrial import inner membrane translocase complex	`GO:0001405` GO:0001405 places the PAM import motor as part of the TIM23 complex.
PAM complex, Tim23 associated import motor	acts at	mitochondrial matrix	`GO:0001405` GO:0001405 defines PAM as located on the matrix side of the mitochondrial inner membrane.
PAM complex, Tim23 associated import motor	supports	protein import into mitochondrial matrix	`GO:0001405` GO:0001405 defines ATPase motor activity that drives mitochondrial matrix import as a feature of PAM. `DOI:10.1016/j.cell.2009.08.005` Chacinska et al. 2009 reviewed the TIM23-PAM pathway for mitochondrial presequence import.

Discussions

CURATION_TODO (OPEN): Resolve exact source-neutral family groundings and stable TIM23/PAM motor boundaries before adding Pam or Hsp70-cycle rows. GO exactly grounds the PAM motor itself, and primary budding-yeast studies define J-protein participation in the TIM23-associated motor, but this first record leaves individual Pam, Tim, and mitochondrial-Hsp70 cycle rows unasserted until exact family groundings are separated from stable constituent versus transient import-motor associations.

Evidence

GO:0001405 Gene Ontology cellular-component term for the presequence translocase-associated PAM import motor.
GO:0098800 Gene Ontology cellular-component parent term for inner mitochondrial membrane protein complexes.
GO:0005744 Gene Ontology cellular-component term for the TIM23 inner-membrane translocase that PAM associates with.
GO:0005759 Gene Ontology cellular-component term for the mitochondrial matrix on whose side PAM is located.
GO:0030150 Gene Ontology biological-process term for protein import into the mitochondrial matrix.
DOI:10.1016/j.cell.2009.08.005 Chacinska et al. 2009, 'Importing mitochondrial proteins: machineries and mechanisms', Cell.
DOI:10.1093/emboj/cdg485 Mokranjac et al. 2003, 'Tim14, a novel key component of the import motor of the TIM23 protein translocase of mitochondria', The EMBO Journal.
DOI:10.1083/jcb.200308004 Truscott et al. 2003, 'A J-protein is an essential subunit of the presequence translocase-associated protein import motor of mitochondria', Journal of Cell Biology.

Curation history

2026-09-18T18:08:25Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-18T18:09:41Z codex · EXPANDED_RECORD — Added GO synonymy, inner-mitochondrial-membrane protein-complex parentage, TIM23 and mitochondrial-matrix parthood, Saccharomyces scope, matrix-import function evidence, a nonmechanistic PAM matrix-import graph, and a PAM subunit-boundary TODO.
2026-09-18T18:20:18Z codex · ADDRESS_REVIEW — Resolved #1179 by narrowing the PAM canonical example from plural J-protein components to the cited J-protein component.

Source: data/structures/other/pam_complex_tim23_associated_import_motor.yaml