TIM18/YOR297C Summary Help

Standard Name TIM18 1, 2
Systematic Name YOR297C
Feature Type ORF, Verified
Description Component of the mitochondrial TIM22 complex; involved in insertion of polytopic proteins into the inner membrane; may mediate assembly or stability of the complex (1, 2, 3 and see Summary Paragraph)
Name Description Translocase of the Inner Mitochondrial membrane 2
Chromosomal Location
ChrXV:875321 to 874743 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Gene Ontology Annotations All TIM18 GO evidence and references
  View Computational GO annotations for TIM18
Molecular Function
Manually curated
Biological Process
Manually curated
Cellular Component
Manually curated
Regulators 3 genes
Classical genetics
Large-scale survey
256 total interaction(s) for 189 unique genes/features.
Physical Interactions
  • Affinity Capture-MS: 2
  • Affinity Capture-RNA: 2
  • Affinity Capture-Western: 17
  • Co-fractionation: 1
  • Co-purification: 1
  • PCA: 1
  • Reconstituted Complex: 1

Genetic Interactions
  • Dosage Rescue: 9
  • Negative Genetic: 167
  • Phenotypic Enhancement: 1
  • Positive Genetic: 34
  • Synthetic Growth Defect: 14
  • Synthetic Lethality: 6

Expression Summary
Length (a.a.) 192
Molecular Weight (Da) 21,972
Isoelectric Point (pI) 9.12
Phosphorylation PhosphoGRID | PhosphoPep Database
sequence information
ChrXV:875321 to 874743 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Last Update Coordinates: 2011-02-03 | Sequence: 2011-02-03
Subfeature details
Most Recent Updates
Coordinates Sequence
CDS 1..579 875321..874743 2011-02-03 2011-02-03
Retrieve sequences
Analyze Sequence
S288C only
S288C vs. other species
S288C vs. other strains
External Links All Associated Seq | Entrez Gene | Entrez RefSeq Protein | MIPS | Search all NCBI (Entrez) | UniProtKB
Primary SGDIDS000005823

About mitochondrial import

While the mitochondrial genome encodes a handful of proteins, most of the hundreds of proteins that reside in the mitochondrion are encoded by nuclear genes, translated in the cytoplasm, and imported into mitochondria via a series of complex molecular machines (see 4, 5 for review). Many of the proteins imported into mitochondria are involved in respiration, which is not an essential process: S. cerevisiae is able to carry out either fermentative growth on carbon sources such as glucose, or respiratory growth on nonfermentable carbon sources such as glycerol and ethanol. However, since maintenance of the mitochondrial compartment is essential to life, mutations that completely disrupt mitochondrial import are lethal.

About the TIM22 complex

The TIM22 complex of the mitochondrial inner membrane mediates the insertion of large hydrophobic proteins, typically transporters (carrier proteins) with multiple transmembrane segments, into the inner membrane. These proteins travel through the outer membrane via the translocase of the outer mitochondrial membrane (TOM) complex. Their transit across the intermembrane space to the TIM22 complex in the inner membrane is mediated by complexes of small soluble protein chaperones: Tim8p with Tim13p, and Tim9p with Tim10p. The membrane-embedded core of the TIM22 complex consists of Tim54p, Tim22p, Tim18p, and Sdh3p (6); additionally, the small Tim proteins Tim9p, Tim10p, and Tim12p are associated with the complex on the intermembrane space side (reviewed in 7, 5).

about TIM18

Tim18p is a nonessential, but integral, component of the TIM22 complex (2, 1, 8). Its role in the complex is unclear, but it is thought to facilitate assembly of Tim54p into the complex (9).The protein is embedded in the mitochondrial inner membrane with its C terminus exposed to the intermembrane space (1). The tim18 null mutant is viable but displays cold-sensitive fermentative growth and slow respiratory growth, and in vitro import of mitochondrial inner membrane protein substrates of the TIM22 complex is delayed in extracts from the null mutant (2, 1). The null mutant is also petite-negative, meaning that it cannot survive loss of the mitochondrial genome (1). In addition, the null mutant is resistant to some stresses that stimulate apoptosis, such as arsenic, hydrogen peroxide, and hyperosmolarity (10).

Last updated: 2009-03-17 Contact SGD

References cited on this page View Complete Literature Guide for TIM18
1) Kerscher O, et al.  (2000) Tim18p is a new component of the Tim54p-Tim22p translocon in the mitochondrial inner membrane. Mol Biol Cell 11(1):103-16
2) Koehler CM, et al.  (2000) Tim18p, a new subunit of the TIM22 complex that mediates insertion of imported proteins into the yeast mitochondrial inner membrane. Mol Cell Biol 20(4):1187-93
3) Rehling P, et al.  (2003) Insertion of hydrophobic membrane proteins into the inner mitochondrial membrane--a guided tour. J Mol Biol 326(3):639-57
4) Neupert W and Herrmann JM  (2007) Translocation of proteins into mitochondria. Annu Rev Biochem 76:723-49
5) Mokranjac D and Neupert W  (2009) Thirty years of protein translocation into mitochondria: unexpectedly complex and still puzzling. Biochim Biophys Acta 1793(1):33-41
6) Gebert N, et al.  (2011) Dual Function of Sdh3 in the Respiratory Chain and TIM22 Protein Translocase of the Mitochondrial Inner Membrane. Mol Cell 44(5):811-8
7) Bolender N, et al.  (2008) Multiple pathways for sorting mitochondrial precursor proteins. EMBO Rep 9(1):42-9
8) Rehling P, et al.  (2003) Protein insertion into the mitochondrial inner membrane by a twin-pore translocase. Science 299(5613):1747-51
9) Wagner K, et al.  (2008) The assembly pathway of the mitochondrial carrier translocase involves four preprotein translocases. Mol Cell Biol 28(13):4251-60
10) Du L, et al.  (2007) Tim18, a component of the mitochondrial translocator, mediates yeast cell death induced by arsenic. Biochemistry (Mosc) 72(8):843-7