Conserved GxxxG and WN motifs of MIC13 are essential for bridging two MICOS subcomplexes

Structural insights into crista junction formation by the Mic60-Mic19 complex

“…The Mic60 module of MICOS links CJs to the mitochondrial outer membrane through formation of membrane contact sites with different partner protein complexes, like the sorting and assembly machinery for β-barrel proteins (SAM complex) (9,10,(21)(22)(23)(33)(34)(35)(36)(37). Mic12 in yeast or MIC13/QIL1 in higher eukaryotes connect the Mic60 and Mic10 modules of MICOS (28,38,39). Loss of MICOS components leads to a massively altered cristae morphology in all organisms examined so far.…”

Decoding and influencing mitochondrial inner membrane ultra-structure biogenesis

“…It was found that glycine residues at positions 50 and 52 in the GxGxG motif of TM1 of yeast Mic10 is essential for its homo-oligomerization activity. These GxxxG motifs, also present in other proteins such as F1FO-ATP Synthase at CT or reticulons in the endoplasmic reticulum (ER) are responsible for helix-helix packing and oligomerization (Russ & Engelman, 2000;Urbach et al, 2021;Voeltz et al, 2006).…”

“…These glycine-rich motifs are especially important for transmembrane helix packing and thus oligomerization (Russ & Engelman, 2000). A large number of proteins have already been discovered to use their GxxxG motifs for oligomerization (Arnold et.al, 1998;Wagner et al, 2009;Demishtein-Zohary et al, 2017;Urbach et al, 2021). It was shown via SDS-PAGE as well as BN-PAGE (Bohnert et al, 2015) that detergent solubilized yeast Mic10 could indeed form stable homo-oligomers mediated by its GxGxG motifs (Barbot et al, 2015).…”

“…shown to be successful in other MICOS sub-units like MIC13 (Urbach et al, 2021). This would enable us to determine the TM that might be more important for the protein's homooligomerization function.…”

“…These structures are ubiquitous features of all mitochondria(Davies et al, 2011;Mukherjee et al, 2021;Strauss et al, 2008). The sub-units e and g possess one conserved TM also consisting of a GxxxG glycine-rich motif that facilitates the assembly of a dimer(Voeltz et al, 2006;Russ & Engelman, 2000;Urbach et al, 2021). The direct link between ATP-Synthase dimerization and cristae biogenesis was first studied in yeast(Habersetzer et al, 2013;Paumard, 2002).…”