10/💰 This study was made possible by funding from the NIH, CIHR, CFI, NSERC, NFRF, HHWF, @moorefound.bsky.social @simonsfoundation.org @snsf.ch 🇺🇸🇨🇦🇨🇭

9/ 📣 This was a wonderful collaboration with the daCosta Lab at @uottawa.ca.

A big shout-out to my 🦋-less co-firsts Melody Nguyen and Tristan Bell and to all co-authors. @lukechao.bsky.social

Thanks to the HMS EM facility, HMS MIcRoN, and the MIT.nano cryo-EM facility for their support.

8/🎯 Our observations reflect a lack of correlation between respiratory function and cristae attachment.

Instead, we observe other morphological cristae defects associated with compromised respiration.

By identifying functional key residues, this work paves the way for future mechanistic studies.

7/🔬 Using TEM, cryo-ET and fluorescence microscopy, we describe a phenotype that is specific to a mutant of these four ASR-identified residues, which features box-like shaped cristae and longer average cristae lengths.

6/🔬 Several TEM studies have shown that Mic60 and Mitofilin deletions result in detached cristae. We observe the same phenotype for our knockout variants. ✅

🤯 Surprisingly, Mitofilin ancestors which rescue respiratory growth like wildtype have knockout-like detached cristae.

5/🎯 Comparing reconstructed ancestors, we identified four residues in the Mitofilin domain that are sufficient for rescuing respiration.

4/🧫 We found that common Mitofilin ancestors as far back as the putative last opisthokont common ancestor #LOCA rescues respiration in yeast. ✅

3/❓How did Mitofilin-supported respiration diverge between yeast 🍺 and humans 👤?

💻🦖🧪 We used ancestral sequence reconstruction #ASR to reconstruct ancestral Mitofilin sequences and resurrected them for in vivo characterization.

2/ 🧫 Using respiratory growth assays, we found that swapping the yeast Mitofilin domain with that of another yeast rescued respiration. ✅

Replacing it with human or bacterial homologues at the endogenous locus did not rescue respiration. 💀

❗This is in contrast to previous plasmid-based work.

1/ ❓Mic60, a core component of the #MICOS complex in the #mitochondrial inner membrane, is crucial for the organization of #cristae and their functions. It's unclear, how Mic60's #Mitofilin domain encodes cristae-supported functions like cellular respiration.

A big shout-out to my incredible team mates Simon Jenni, Coby Garcia, Melody Nguyen, Xuewu Zhang and @lukechao.bsky.social