Editing Crista (section)

==Background==

With the discovery of the dual-membrane nature of mitochondria, the pioneers of mitochondrial [[ultrastructure|ultrastructural]] research proposed different models for the organization of the mitochondrial inner membrane.<ref name=Griparic2001>{{cite journal|last1=Griparic|first1=L|last2=van der Bliek|first2=AM|s2cid=9500863|title=The many shapes of mitochondrial membranes.|journal=Traffic|date=August 2003|volume=2|issue=4|pages=235–44|pmid=11285133|doi=10.1034/j.1600-0854.2001.1r008.x| doi-access = free }}</ref> Three models proposed were:

*'''Baffle model''' – According to [[George Emil Palade|Palade]] (1953), the mitochondrial inner membrane is convoluted in a baffle-like manner with broad openings towards the intra-cristal space. This model entered most textbooks and was widely believed for a long time.
*'''Septa model''' – [[Fritiof S. Sjöstrand|Sjöstrand]] (1953) suggested that sheets of inner membrane are spanned like septa (plural of [[septum]]) through the matrix, separating it into several distinct compartments.<ref>{{cite journal|last1=Sjostrand|first1=F|title=Systems of double membranes in the cytoplasm of certain tissue cells|journal=Nature|date=Jan 3, 1953|volume=171|issue=4340|pages=31–32|doi=10.1038/171031a0|s2cid=6765607}}</ref>
*'''Crista junction model''' – Daems and Wisse (1966) proposed that cristae are connected to the inner boundary membrane via tubular structures characterized by rather small diameters, termed crista junctions (CJs). In the middle of 1990s these structures were rediscovered by EM tomography, leading to the establishment of this currently widely accepted model.<ref>{{cite journal|last1=Zick|first1=M|last2=Rabl|first2=R|last3=Reichert|first3=AS|title=Cristae formation-linking ultrastructure and function of mitochondria.|journal=Biochimica et Biophysica Acta (BBA) - Molecular Cell Research|date=January 2009|volume=1793|issue=1|pages=5–19|pmid=18620004|doi=10.1016/j.bbamcr.2008.06.013|doi-access=free}}</ref>

More recent research (2019) finds rows of [[ATP synthase]] dimers (formerly known as "elementary particles" or "oxysomes") forming at the cristae. These membrane-curving dimers have a bent shape, and may be the first step to cristae formation.<ref>{{cite journal | vauthors = Blum TB, Hahn A, Meier T, Davies KM, Kühlbrandt W | title = Dimers of mitochondrial ATP synthase induce membrane curvature and self-assemble into rows | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 116 | issue = 10 | pages = 4250–4255 | date = March 2019 | pmid = 30760595 | doi = 10.1073/pnas.1816556116 | pmc = 6410833| bibcode = 2019PNAS..116.4250B | doi-access = free }}</ref> They are situated at the base of the crista. A mitochondrial contact site cristae organizing system (MICOS) protein complex occupies the crista junction. Proteins like [[Dynamin-like 120 kDa protein|OPA1]] are involved in cristae remodeling.<ref name=baker>{{cite journal |last1=Baker |first1=Nicole |last2=Patel |first2=Jeel |last3=Khacho |first3=Mireille |title=Linking mitochondrial dynamics, cristae remodeling and supercomplex formation: How mitochondrial structure can regulate bioenergetics |journal=Mitochondrion |date=November 2019 |volume=49 |pages=259–268 |doi=10.1016/j.mito.2019.06.003|pmid=31207408 |doi-access=free }}</ref>

Crista are traditionally sorted by shapes into lamellar, tubular, and vesicular cristae.<ref>{{cite journal | vauthors = Hanaki M, Tanaka K, Kashima Y | year = 1985 | title = Scanning electron icroscopic study on mitochondrial cristae in the rat adrenal cortex | journal = Journal of Electron Microscopy | volume = 34 | issue = 4 | pages = 373–380 | pmid = 3837809 | language = en }}</ref> They appear in different cell types. It is debated whether these shapes arise by different pathways.<ref>{{cite journal |last1=Stephan |first1=Till |last2=Roesch |first2=Axel |last3=Riedel |first3=Dietmar |last4=Jakobs |first4=Stefan |title=Live-cell STED nanoscopy of mitochondrial cristae |journal=Scientific Reports |date=27 August 2019 |volume=9 |issue=1 |page=12419 |doi=10.1038/s41598-019-48838-2|pmid=31455826 |pmc=6712041 |bibcode=2019NatSR...912419S }}</ref>