Mitochondrial inner membrane translocase subunit Tim17/Tim22/Tim23/peroxisomal protein PMP24 (IPR003397)

Short name: Tim17/Tim22/Tim23/PMP24

Overlapping homologous superfamilies


Family relationships


The membrane-embedded multi-protein complexes of mitochondria mediate the transport of nuclear-encoded proteins across and into the outer or inner mitochondrial membranes [PMID: 15232570]. The TOM (translocase of the outer mitochondrial membrane) complex consists of cytosol-exposed receptors and a pore-forming core, and mediates the transport of proteins from the cytosol across and into the outer mitochondrial membrane. A novel protein complex in the outer membrane of mitochondria, called the SAM complex (sorting and assembly machinery), is involved in the biogenesis of beta-barrel proteins of the outer membrane. Two translocases of the inner mitochondrial membrane (TIM22 and TIM23 complexes) mediate protein transport at the inner membrane.

The TIM23 complex (a presequence translocase) mediates the transport of presequence-containing proteins across and into the inner membrane. Tim23 and Tim17 form part of this complex. Tim23 forms a pore in the inner membrane. The role of Tim17 is not yet fully understood. The TIM22 complex (a twin-pore carrier translocase) catalyses the insertion of multi-spanning proteins that have internal targeting signals into the inner membrane. The TIM22 complex mediates the membrane insertion of multi-spanning inner-membrane proteins that have internal targeting signals, and it uses the membrane potential as an external driving force. The Tim22 subunit of the mitochondrial import inner membrane translocase is included in this family.

This family also includes Pmp24, a peroxisomal membrane protein, and NADH ubiquinone dehydrogenase 1 alpha subunit 11. Pmp24 was previously known as Pmp27 [PMID: 7721939].

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.