The structure of the inner mitochondrial membrane is extensively folded and compartmentalized. The numerous invaginations of the membrane are called cristae, separated by crista junctions from the inner boundary membrane juxtaposed to the outer membrane. Cristae significantly increase the total membrane surface area compared to a smooth inner membrane and thereby the available working space for oxidative phosphorylation.
The inner membrane creates two compartments. The region between the inner and outer membrane, called the intermembrane space, is largely continuous with the cytosol, while the more sequestered space inside the inner membrane is called the matrix.
For typical liver mitochondria, the area of the inner membrane is about 5 times as large as the outer membrane due to cristae. This ratio is variable and mitochondria from cells that have a greater demand for ATP, such as muscle cells, contain even more cristae. Cristae membranes are studded on the matrix side with small round protein complexes known as F1 particles, the site of proton-gradient driven ATP synthesis. Cristae affect overall chemiosmotic function of mitochondria.[1]
Cristae junctionsedit
Cristae and the inner boundary membranes are separated by junctions. The end of cristae are partially closed by transmembrane protein complexes that bind head to head and link opposing crista membranes in a bottleneck-like fashion.[2] For example, deletion of the junction protein IMMT leads to a reduced inner membrane potential and impaired growth[3] and to dramatically aberrant inner membrane structures which form concentric stacks instead of the typical invaginations.[4]
Compositionedit
The inner membrane of mitochondria is similar in lipid composition to the membrane of bacteria. This phenomenon can be explained by the endosymbiont hypothesis of the origin of mitochondria as prokaryotes internalized by a eukaryotic host cell.
In the inner mitochondrial membrane, the protein-to-lipid ratio is 80:20, in contrast to the outer membrane, which is 50:50.[7]
Permeabilityedit
The inner membrane is freely permeable to oxygen, carbon dioxide, and water only.[8] It is much less permeable to ions and small molecules than the outer membrane, creating compartments by separating the matrix from the cytosolic environment. This compartmentalization is a necessary feature for metabolism. The inner mitochondrial membrane is both an electrical insulator and chemical barrier. Sophisticated ion transporters exist to allow specific molecules to cross this barrier. There are several antiport systems embedded in the inner membrane, allowing exchange of anions between the cytosol and the mitochondrial matrix.[7]
^Mannella CA (2006). "Structure and dynamics of the mitochondrial inner membrane cristae". Biochimica et Biophysica Acta (BBA) - Molecular Cell Research. 1763 (5–6): 542–548. doi:10.1016/j.bbamcr.2006.04.006. PMID 16730811.
^Herrmann, JM (18 October 2011). "MINOS is plus: a Mitofilin complex for mitochondrial membrane contacts". Developmental Cell. 21 (4): 599–600. doi:10.1016/j.devcel.2011.09.013. PMID 22014515.
^von der Malsburg, K; Müller, JM; Bohnert, M; Oeljeklaus, S; Kwiatkowska, P; Becker, T; Loniewska-Lwowska, A; Wiese, S; Rao, S; Milenkovic, D; Hutu, DP; Zerbes, RM; Schulze-Specking, A; Meyer, HE; Martinou, JC; Rospert, S; Rehling, P; Meisinger, C; Veenhuis, M; Warscheid, B; van der Klei, IJ; Pfanner, N; Chacinska, A; van der Laan, M (18 October 2011). "Dual role of mitofilin in mitochondrial membrane organization and protein biogenesis" (PDF). Developmental Cell. 21 (4): 694–707. doi:10.1016/j.devcel.2011.08.026. PMID 21944719.
^Rabl, R; Soubannier, V; Scholz, R; Vogel, F; Mendl, N; Vasiljev-Neumeyer, A; Körner, C; Jagasia, R; Keil, T; Baumeister, W; Cyrklaff, M; Neupert, W; Reichert, AS (15 June 2009). "Formation of cristae and crista junctions in mitochondria depends on antagonism between Fcj1 and Su e/g". The Journal of Cell Biology. 185 (6): 1047–63. doi:10.1083/jcb.200811099. PMC2711607. PMID 19528297.
^Comte J, Maïsterrena B, Gautheron DC (January 1976). "Lipid composition and protein profiles of outer and inner membranes from pig heart mitochondria. Comparison with microsomes". Biochim. Biophys. Acta. 419 (2): 271–84. doi:10.1016/0005-2736(76)90353-9. PMID 1247555.
^Lomize, Andrel; Lomize, Mikhail; Pogozheva, Irina (2013). "Membrane Protein Lipid Composition Atlas". Orientations of Proteins in Membranes. University of Michigan. Retrieved 10 April 2014.
^ abKrauss, Stefan (2001). (PDF). Nature Publishing Group. Archived from the original (PDF) on 21 October 2012. Retrieved 9 April 2014.
^Caprette, David R. (12 December 1996). "Structure of Mitochondria". Experimental Biosciences. Rice University. Retrieved 9 April 2014.
External linksedit
Mitochondrial inner membrane (97 proteins) Orientations of Proteins in Membranes (OPM) database
January 01, 1970
inner, mitochondrial, membrane, inner, mitochondrial, membrane, mitochondrial, membrane, which, separates, mitochondrial, matrix, from, intermembrane, space, cell, biologymitochondrioncomponents, typical, mitochondrion, outer, membrane, porin, intermembrane, s. The inner mitochondrial membrane IMM is the mitochondrial membrane which separates the mitochondrial matrix from the intermembrane space Cell biologymitochondrionComponents of a typical mitochondrion 1 Outer membrane 1 1 Porin 2 Intermembrane space 2 1 Intracristal space 2 2 Peripheral space 3 Lamella 3 1 Inner membrane You are here3 11 Inner boundary membrane 3 12 Cristal membrane dd 3 2 Matrix 3 3 Cristae 4 Mitochondrial DNA 5 Matrix granule 6 Ribosome 7 ATP synthase Contents 1 Structure 1 1 Cristae 1 2 Cristae junctions 2 Composition 3 Permeability 4 IMM associated proteins 5 See also 6 References 7 External linksStructure editThe structure of the inner mitochondrial membrane is extensively folded and compartmentalized The numerous invaginations of the membrane are called cristae separated by crista junctions from the inner boundary membrane juxtaposed to the outer membrane Cristae significantly increase the total membrane surface area compared to a smooth inner membrane and thereby the available working space for oxidative phosphorylation The inner membrane creates two compartments The region between the inner and outer membrane called the intermembrane space is largely continuous with the cytosol while the more sequestered space inside the inner membrane is called the matrix Cristae edit Main article Cristae For typical liver mitochondria the area of the inner membrane is about 5 times as large as the outer membrane due to cristae This ratio is variable and mitochondria from cells that have a greater demand for ATP such as muscle cells contain even more cristae Cristae membranes are studded on the matrix side with small round protein complexes known as F1 particles the site of proton gradient driven ATP synthesis Cristae affect overall chemiosmotic function of mitochondria 1 Cristae junctions edit Cristae and the inner boundary membranes are separated by junctions The end of cristae are partially closed by transmembrane protein complexes that bind head to head and link opposing crista membranes in a bottleneck like fashion 2 For example deletion of the junction protein IMMT leads to a reduced inner membrane potential and impaired growth 3 and to dramatically aberrant inner membrane structures which form concentric stacks instead of the typical invaginations 4 Composition editThe inner membrane of mitochondria is similar in lipid composition to the membrane of bacteria This phenomenon can be explained by the endosymbiont hypothesis of the origin of mitochondria as prokaryotes internalized by a eukaryotic host cell In pig heart mitochondria phosphatidylethanolamine makes up the majority of the inner mitochondrial membrane at 37 0 of the phospholipid composition Phosphatidylcholine makes up about 26 5 cardiolipin 25 4 and phosphatidylinositol 4 5 5 In S cerevisiae mitochondria phosphatidylcholine makes up 38 4 of the IMM phosphatidylethanolamine makes up 24 0 phosphatidylinositol 16 2 cardiolipin 16 1 phosphatidylserine 3 8 and phosphatidic acid 1 5 6 In the inner mitochondrial membrane the protein to lipid ratio is 80 20 in contrast to the outer membrane which is 50 50 7 Permeability editThe inner membrane is freely permeable to oxygen carbon dioxide and water only 8 It is much less permeable to ions and small molecules than the outer membrane creating compartments by separating the matrix from the cytosolic environment This compartmentalization is a necessary feature for metabolism The inner mitochondrial membrane is both an electrical insulator and chemical barrier Sophisticated ion transporters exist to allow specific molecules to cross this barrier There are several antiport systems embedded in the inner membrane allowing exchange of anions between the cytosol and the mitochondrial matrix 7 IMM associated proteins editElectron transport chain NADH dehydrogenase ubiquinone Electron transferring flavoprotein dehydrogenase Electron transferring flavoprotein Succinate dehydrogenase Alternative oxidase Cytochrome bc1 complex Cytochrome c Cytochrome c oxidase F ATPase ATP ADP translocase ATP binding cassette transporter Cholesterol side chain cleavage enzyme Protein tyrosine phosphatase Carnitine O palmitoyltransferase Carnitine O acetyltransferase Carnitine O octanoyltransferase Cytochrome P450 Translocase of the inner membrane Glutamate aspartate transporter Pyrimidine metabolism Dihydroorotate dehydrogenase Thymidylate synthase FAD HtrA serine peptidase 2 Adrenodoxin reductase Heme biosynthesis Protoporphyrinogen oxidase Ferrochelatase Uncoupling proteinSee also editCitric acid cycle Proton gradient Mitochondrial trifunctional protein Mitochondrial shuttle Transport proteinsReferences edit Mannella CA 2006 Structure and dynamics of the mitochondrial inner membrane cristae Biochimica et Biophysica Acta BBA Molecular Cell Research 1763 5 6 542 548 doi 10 1016 j bbamcr 2006 04 006 PMID 16730811 Herrmann JM 18 October 2011 MINOS is plus a Mitofilin complex for mitochondrial membrane contacts Developmental Cell 21 4 599 600 doi 10 1016 j devcel 2011 09 013 PMID 22014515 von der Malsburg K Muller JM Bohnert M Oeljeklaus S Kwiatkowska P Becker T Loniewska Lwowska A Wiese S Rao S Milenkovic D Hutu DP Zerbes RM Schulze Specking A Meyer HE Martinou JC Rospert S Rehling P Meisinger C Veenhuis M Warscheid B van der Klei IJ Pfanner N Chacinska A van der Laan M 18 October 2011 Dual role of mitofilin in mitochondrial membrane organization and protein biogenesis PDF Developmental Cell 21 4 694 707 doi 10 1016 j devcel 2011 08 026 PMID 21944719 Rabl R Soubannier V Scholz R Vogel F Mendl N Vasiljev Neumeyer A Korner C Jagasia R Keil T Baumeister W Cyrklaff M Neupert W Reichert AS 15 June 2009 Formation of cristae and crista junctions in mitochondria depends on antagonism between Fcj1 and Su e g The Journal of Cell Biology 185 6 1047 63 doi 10 1083 jcb 200811099 PMC 2711607 PMID 19528297 Comte J Maisterrena B Gautheron DC January 1976 Lipid composition and protein profiles of outer and inner membranes from pig heart mitochondria Comparison with microsomes Biochim Biophys Acta 419 2 271 84 doi 10 1016 0005 2736 76 90353 9 PMID 1247555 Lomize Andrel Lomize Mikhail Pogozheva Irina 2013 Membrane Protein Lipid Composition Atlas Orientations of Proteins in Membranes University of Michigan Retrieved 10 April 2014 a b Krauss Stefan 2001 Mitochondria Structure and Role in Respiration PDF Nature Publishing Group Archived from the original PDF on 21 October 2012 Retrieved 9 April 2014 Caprette David R 12 December 1996 Structure of Mitochondria Experimental Biosciences Rice University Retrieved 9 April 2014 External links editMitochondrial inner membrane 97 proteins Orientations of Proteins in Membranes OPM database Retrieved from https en wikipedia org w index php title Inner mitochondrial membrane amp oldid 1207866378, wikipedia, wiki, book, books, library,
