TCDB is operated by the Saier Lab Bioinformatics Group

Mitochondrial protein translocase (MPT) (Chacinska et al., 2005; Mokranjac et al., 2005; Bihlmaier et al., 2007). The crystal structure of the intermembrane space domain of yeast Tim50 has been solved to 1.83 Å resolution (Qian et al., 2011). A protruding beta-hairpin of Tim50 is crucial for interaction with Tim23, providing a molecular basis for the cooperation of Tim50 and Tim23 in preprotein translocation to the protein-conducting channel of the mitochondrial inner membrane (Qian et al., 2011).  TIM23-mediates insertion of transmembrane α-helices into the mitochondrial inner membrane (Botelho et al., 2011). The TIM23 channel undergoes structural changes in response to the energized state of the membrane, the pmf (Malhotra et al. 2013).  TMS1 in TIM23 is required for homodimerization while it and TMS2 are involved in pre-protein binding in the channel (Pareek et al. 2013).  The Tom40 outer membrane channel may be a 19 β-stranded barrel, possibly homologous to the VDAC porins (TC# 1.B.8) (Lackey et al. 2014).  Tim23 and Tim17 interact with each other as well as Tim44 and Pam17, respectively.  These last two proteins may serve regulatory functions (Ting et al. 2014).  Tom20, 22, 40 and 70 recognize presequences in various mitochondrially targetted proteins (Melin et al. 2015; Melin et al. 2014).  In the 4 TMS TIM17 protein, mutations in TMSs1 and 2 impair the interaction of Tim17 with Tim23, whereas mutations in TM3 compromise binding of the import motor (Demishtein-Zohary et al. 2017); further, residues in the matrix-facing region of Tim17 involved in binding of the import motor were identified. TIM22, forms an intramolecular disulfide bond in yeast and humans.  If not oxidized, they do not properly integrate into the membrane complex, and the lack of Tim17 oxidation disrupts the TIM23 translocase complex (Wrobel et al. 2016). Mgr2 (TC# 1.A.111.1.3) and Pam18 are involved in precursormembrane protein quality control (Schendzielorz et al. 2018).


MPT of Saccharomyces cerevisiae Outer Membrane Translocase
Tom5 (channel regulator)
Tom6 (channel regulator)
Tom7 (channel regulator)
Tom20 (receptor)
Tom22 (receptor)
Tom40 (channel) (involved in sorting)
Tom70 (receptor) Inner Membrane Translocase #1 (Tim23 complex)
Tim17 (channel protein)
Tim23 (channel protein)
Tim44 (ATP-dependent motor)
Tim14 (J protein; PAM18; Ylr008c) (motor component)
Tim16 (Pam16) (motor component)
Tim21 (may regulate protein import by binding to both the translocase of the outer membrane (TOM) and presequence-associated motor (PAM) complexes)
Mge1 (motor component)
Mdj2 (J protein that can replace Tim14) Intermembrane Chaperone for the Tim23 Complex
Tim50 Inner Membrane Translocase #2 (Tim22 complex)
Tim22 (channel protein)
Tim54 (channel protein)
Tim18 (channel protein) Intermembrane Chaperones for the Tim22 Complex
Tim8 (targeting protein)
Tim9 (targeting protein)
Tim10 (targeting protein)
Tim13 (targeting protein) Intermembrane (IM) Proteins involved in uniport and assembly of other intermembrane proteins, Mia40 and Erv1 (Chacinska et al., 2004; Grumbt et al., 2007))
Mia40 (403aas)
Erv1 (P27882)

Hydrogenosome multicomponent protein import complex.

Import complex of Trichomonas vaginalis
Small TIM9-10A, 74 aas, A2FKF0
Small TIM9-10B, 74 aas, A2DZ11
Tim17A/B protein, 160 aas, A2DDM1
Tim17C, 159 aas, A2FHN8
Tim17D, 157 aas, 4 TMSs, A2DXD3
Tim17-like, 170 aas, A2DS29
Tim44, 326 aas, A2F7V1
Pam16, 111 aas, A2FE18
Pam18, 117 aas, A2DFA6