TIM22/YDL217C Summary Help

TIM22 BASIC INFORMATION

Standard Name TIM22 1
Systematic Name YDL217C
Feature Type ORF, Verified
Description Essential core component of the mitochondrial TIM22 complex involved in insertion of polytopic proteins into the inner membrane; forms the channel through which proteins are imported (1, 2, 3, 4, 5, 6 and see Summary Paragraph)
Name Description Translocase of the Inner Mitochondrial membrane
GO Annotations All TIM22 GO evidence and references
    View Computational GO annotations for TIM22
Molecular Function
Manually curated
Biological Process
Manually curated
Cellular Component
Manually curated
High-throughput
Mutant Phenotype All TIM22 Phenotype details and references
Classical genetics
conditional
null
repressible
Large-scale survey
null
Interactions TIM22 All interactions details and references
26 total interaction(s) for 11 unique genes/features.
Physical Interactions
  • Affinity Capture-Western: 11
  • Co-fractionation: 2
  • Co-purification: 1
  • Reconstituted Complex: 4
  • Two-hybrid: 2
Genetic Interactions
  • Dosage Rescue: 4
  • Synthetic Growth Defect: 2
Sequence Information
ChrIV:68607 to 67984 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Gbrowse
Last Update Coordinates: 1996-07-31 | Sequence: 1996-07-31
Subfeature details
Relative
Coordinates		 Chromosomal
Coordinates		 Most Recent Updates
Coordinates Sequence
CDS 1..624 68607..67984 1996-07-31 1996-07-31
External Links All Associated Seq | Entrez Gene | Entrez RefSeq Protein | MIPS | UniProtKB
Primary SGDIDS000002376

TIM22 RESOURCES

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SGD ORF map
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Click on histogram for expression summary
Expression Summary histogram

ADDITIONAL INFORMATION for TIM22

SUMMARY PARAGRAPH for TIM22

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 7, 8 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, and Tim18p; additionally, the small Tim proteins Tim9p, Tim10p, and Tim12p are associated with the complex on the intermembrane space side (reviewed in 9, 8).

About TIM22

Tim22p is the only essential component of the membrane-embedded core of the TIM22 complex. The protein has sequence similarity to Tim17p and Tim23p (1). It has four transmembrane helices that form a hydrophilic, voltage-activated channel through the inner membrane. Purified Tim22p is capable of inserting substrate proteins into the inner membrane even in the absence of the other components of the core TIM22 complex, Tim54p and Tim18p, although with a greatly reduced efficiency (10). Thus, Tim22p appears to be the central component of the complex, capable of recognizing the internal targeting signals of the precursor proteins, forming a translocation channel, and inserting the precursors into the inner membrane (10).

Last updated: 2009-10-21

REFERENCES CITED ON THIS PAGE [View Complete Literature Guide for TIM22]

1) Sirrenberg C, et al.  (1996) Import of carrier proteins into the mitochondrial inner membrane mediated by Tim22. Nature 384(6609):582-5
2) 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
3) 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
4) Jensen RE and Dunn CD  (2002) Protein import into and across the mitochondrial inner membrane: role of the TIM23 and TIM22 translocons. Biochim Biophys Acta 1592(1):25-34
5) Rehling P, et al.  (2003) Protein insertion into the mitochondrial inner membrane by a twin-pore translocase. Science 299(5613):1747-51
6) 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
7) Neupert W and Herrmann JM  (2007) Translocation of proteins into mitochondria. Annu Rev Biochem 76:723-49
8) 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
9) Bolender N, et al.  (2008) Multiple pathways for sorting mitochondrial precursor proteins. EMBO Rep 9(1):42-9
10) Kovermann P, et al.  (2002) Tim22, the essential core of the mitochondrial protein insertion complex, forms a voltage-activated and signal-gated channel. Mol Cell 9(2):363-73