Tic complex

GO:0031897 · Other · Multiprotein complex · Proposed

A chloroplast inner-envelope protein translocon complex that forms the inner-membrane step of nuclear-encoded preprotein import into the chloroplast. [GO:0031897]

Synonyms: TIC complex

Part of: chloroplast inner membrane (GO:0009706)

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

Taxonomic distribution

NCBITaxon:3055 Chlamydomonas reinhardtii — COMMON: Chlamydomonas reinhardtii has a Tic complex in the chloroplast inner envelope that couples with the outer envelope Toc complex in a resolved TOC-TIC import supercomplex. [DOI:10.1016/j.cell.2022.10.030]

Canonical examples

NCBITaxon:3055 Chlamydomonas reinhardtii — Green-algal model in which a chloroplast TOC-TIC supercomplex spanning both envelope membranes was resolved structurally. [DOI:10.1016/j.cell.2022.10.030]

Functions

protein import into chloroplast stroma GO:0045037 — The Tic complex contributes the inner-envelope step of nuclear-encoded preprotein import toward the chloroplast stroma.
- GO:0045037 GO:0045037 defines protein import into the chloroplast stroma.
- DOI:10.1016/j.cell.2022.10.030 Jin et al. 2022 resolved the Tic portion of a Chlamydomonas TOC-TIC supercomplex spanning the chloroplast envelope.

Mechanism graphs

Tic contributes the inner-envelope import step (FUNCTION)

In Chlamydomonas, the Tic complex resides in the chloroplast inner membrane and couples with the outer-envelope Toc complex during stromal preprotein import.

Subject	Predicate	Object	Evidence
Tic complex	is part of	chloroplast inner membrane	`GO:0031897` GO:0031897 defines the Tic complex as the translocon of the inner chloroplast envelope.
Tic complex	couples with	Toc complex	`DOI:10.1016/j.cell.2022.10.030` Jin et al. 2022 resolved a Chlamydomonas TOC-TIC supercomplex spanning the two chloroplast envelope membranes.
Tic complex	routes precursors toward	protein import into chloroplast stroma	`DOI:10.1016/j.cell.2022.10.030` Jin et al. 2022 resolved an inner-envelope Tic portion in a chloroplast protein-import supercomplex.

Discussions

CURATION_TODO (OPEN): Resolve exact source-neutral component groundings for bona fide constituent subfamilies of the inner-envelope Tic translocon before adding subunit-level component rows to this source-neutral Tic record. GO exactly grounds the Tic complex itself, but this record does not assert component-family CURIEs for individual inner-envelope Tic constituents until those families have been curated separately from Toc, Ycf2/FtsHi ATPase, stromal import motors, and other associated chloroplast import factors.

Evidence

GO:0031897 Gene Ontology cellular-component term for the Tic complex.
GO:0032991 Gene Ontology cellular-component term for a protein-containing complex.
GO:0009706 Gene Ontology cellular-component term for the chloroplast inner membrane that carries the Tic complex.
GO:0009941 Gene Ontology cellular-component term for the chloroplast envelope containing the Tic-bearing inner membrane.
GO:0010006 Gene Ontology cellular-component term for the Toc complex, the outer-envelope partner of Tic in stromal preprotein import.
GO:0045037 Gene Ontology biological-process term for protein import into the chloroplast stroma.
DOI:10.1016/j.cell.2022.10.030 Jin et al. 2022, Structure of a TOC-TIC supercomplex spanning two chloroplast envelope membranes, Cell.

Curation history

2026-09-13T04:27:59Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-13T04:28:29Z codex · EXPANDED_RECORD — Added TIC synonymy, protein-complex parentage, chloroplast inner-membrane parthood, Chlamydomonas scope, stromal protein-import function, GO and Jin 2022 evidence, a nonmechanistic Tic/Toc import graph, and a Tic-subunit boundary TODO.
2026-09-13T04:36:29Z codex · ADDRESS_REVIEW — Resolved #750 by narrowing the Tic subunit-boundary TODO to bona fide inner-envelope Tic constituents and excluding broader associated chloroplast import factors from automatic Tic component rows.

Source: data/structures/other/tic_complex.yaml