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Bioenergetics  ·  Article

Cristae and mitochondrial ultrastructure

Cristae are the folds of the mitochondrial inner membrane. Kühlbrandt describes them, from cryo-electron tomography of a mouse heart mitochondrion, as lamellar sheets that criss-cross the matrix and take up most of the organelle's volume in high-demand tissue3. Their shape matters because the respiratory chain and ATP synthase sit in different parts of the fold6. Membrane form and energy conversion are therefore tied together.

Earliest held
1880, Darwin, C.
Most discussed in
Cristae: bridging bioenergetic hubs and…, 2026
In the library
215 passages in 38 works
Rewritten
2026-10-21
18501875190019251950197520002025Wilson, E. B., 18961Lillie, R. S., 19232Kühlbrandt W, 20153Kühlbrandt W, 20154Atlante A, Valenti D, 20215Brzezinski P, Moe A, Ädelroth P, 20216Protasoni M, Zeviani M, 20217Rao J, Wan QQ, Chen L, Tang RB…, 20268Rao J, Wan QQ, Chen L, Tang RB…, 20269
01

Lamellae before mitochondria

In older biological writing, the word lamella was used for other structures, not for cristae. Wilson (1896) reported the view of Bütschli and followers that the fibrillae of protoplasm are optical sections of thin plates, or lamellae, forming the walls of closed chambers1. Lillie (1923) wrote of a semi-permeable surface lamella. In Lillie's account, its temporary breakdown profoundly alters the chemical processes in the cell interior2. These uses concern protoplasm and the cell surface. Neither author connects these lamellae to the inner mitochondrial membrane.

02

Tomography of the folds

Kühlbrandt (2015) reported that cristae vary with tissue. In skeletal and heart muscle they are closely stacked disk-like lamellae. In liver and kidney they are less closely stacked, leaving more room for the matrix3. Atlante and Valenti (2021) divided the inner membrane into the inner boundary membrane and the cristae membranes, joined by junctions that electron tomography showed to be often slit-like5. Kühlbrandt noted that the segregation of proteins between these parts rests mainly on electron microscopy. In cryo-ET, ATP synthase and complex I were not seen in the boundary membrane4.

03

Shaping by ATP synthase

Brzezinski and colleagues (2021) placed the respiratory chain in the flat regions of the cristae and ATP synthase mainly in the bent end regions6. Protasoni and Zeviani (2021) reported that ATP synthase forms dimers and larger assemblies. They placed these at the bottom of the cristae, where they appear to enforce strong local curvature7. Rao and colleagues (2026) described V-shaped dimers in oligomeric rows that induce the curvature at the cristae rim. Disrupting subunits e and g led to loss of cristae tips and onion-like membranes. They added that the role is conserved in Toxoplasma gondii8.

04

Imaging in living cells

Rao and colleagues (2026) argued that electron microscopy gave only static snapshots. They looked to live-cell super-resolution nanoscopy and in situ cryo-electron tomography9. Their stated aim is to see in real time how cristae open and close within milliseconds, acting as metabolic switches during rapid physiological change9. This remains a proposal for future work in their account, not a measured result.

SourcesEach quotation was checked word for word against the passage it opens.
  1. the fibrillae being regarded as the optical sections of thin plates or lamelte which form the walls of closed chambers filled by a more liquid substance.Wilson, E. B., 1896 · The Cell in Development and Inheritance · open at passage 124
  2. the temporary breakdown of the semi-permeable surface-lamella or limiting layer of the protoplasmic emulsion influences profoundly the chemical and other processes occurring in the cell interiorLillie, R. S., 1923 · Protoplasmic Action and Nervous Action · open at passage 605
  3. In tissues with a high energy demand, such as skeletal or heart muscle, the cristae are closely stacked disk-like lamellae that take up most of the mitochondrial volume (Fig. 3).Kühlbrandt W, 2015 · Structure and function of mitochondrial membrane protein complexes · open at passage 14
  4. Cryo-ET of intact mitochondria, which resolves large membrane protein complexes in situ, did not reveal any such assemblies (for example, the ATP synthase or complex I) in the boundary membrane [17]Kühlbrandt W, 2015 · Structure and function of mitochondrial membrane protein complexes · open at passage 13
  5. Both parts are connected via so-called cristae junctions that are often slit-like, as electron tomography has revealed [3].Atlante A, Valenti D, 2021 · A Walk in the Memory, from the First Functional Approach up to Its Regulatory… · open at passage 10
  6. Here, the respiratory chain is located in the flat regions, while the ATP synthases are restricted mainly to the bent end regions5,6 (Figure 1B).Brzezinski P, Moe A, Ädelroth P, 2021 · Structure and Mechanism of Respiratory III-IV Supercomplexes in Bioenergetic… · open at passage 2
  7. These supercomplexes localize specifically at the bottom of the cristae, where they appear to enforce a strong local curvature on the inner membrane, necessary for the formation of the invagination [471].Protasoni M, Zeviani M, 2021 · Mitochondrial Structure and Bioenergetics in Normal and Disease Conditions · open at passage 108
  8. Disruption of these oligomerization subunits (e.g., subunits e and g) leads to the loss of cristae tips and the formation of aberrant onion-like inner membrane structures.Rao J, Wan QQ, Chen L, Tang RB, Killedar D, Tay F, Niu LN, 2026 · Cristae: bridging bioenergetic hubs and compartmental barriers in mitochondrial… · open at passage 40
  9. the future lies in live-cell super-resolution nanoscopy (e.g., STED, SIM) and in situ Cryo-electron tomography.Rao J, Wan QQ, Chen L, Tang RB, Killedar D, Tay F, Niu LN, 2026 · Cristae: bridging bioenergetic hubs and compartmental barriers in mitochondrial… · open at passage 61
Linked ideas
The respiratory chain and ATP synthase whose placement on flat and curved cristae regions is described here.
Cristae geometry is discussed as a way of arranging the proton gradient machinery, including the proton motive force.
Rao and colleagues link ATP synthase shaping of the membrane to optimising the proton motive force.
Fusion proteins such as OPA1 act on the inner membrane and cristae structure.
Disease states are the other setting in which mitochondrial structure and bioenergetics are examined together.
Curvature imposed by protein assemblies is a small-scale case of form arising from physical constraints.
Dimer rows shape cristae ridges and tips, where Rao and colleagues place the enzyme.
Cardiolipin is said to anchor supercomplexes in cristae; loss of mature cardiolipin disintegrates both supercomplexes and cristae in Barth syndrome.
The complexes that exchange quinol sit in the cristae membrane, whose protein density shapes diffusion.
Where it is discussedPassages matching cristae, inner membrane, cryo-ET, cryo-electron tomography
2026Cristae: bridging bioenergetic hubs and compartmental barriers in mitochondrial… · Rao J, Wan QQ, Chen L, Tang RB…63
2015Structure and function of mitochondrial membrane protein complexes · Kühlbrandt W24
2021Mitochondrial Structure and Bioenergetics in Normal and Disease Conditions · Protasoni M, Zeviani M16
2026Adenine Nucleotide Translocase: From Nucleotide Carrier to a Modulator of… · Rauch-Kroehnert U, Heger J, Landmesser…15
1894Materials for the Study of Variation Treated with Especial Regard to… · Bateson, W.11
2022Bioenergetic Aspects of Mitochondrial Actions of Thyroid Hormones · Cioffi F, Giacco A, Goglia F, Silvestri…9
2026Exploring allosteric efflux pump inhibitors and the role of bacterial membrane… · Hada APS, Meena KR, Jitendra, Singh G…7
2020Mitochondrial Bioenergetics and Dynamics in Secretion Processes · Martínez J, Marmisolle I, Tarallo D…6
1923Protoplasmic Action and Nervous Action · Lillie, R. S.6
1992On Growth and Form · Thompson, D. A. W.5