scholarly journals The INs and OUTs of mitofusins

2018 ◽  
Vol 217 (2) ◽  
pp. 439-440 ◽  
Author(s):  
Marta Giacomello ◽  
Luca Scorrano
Keyword(s):  
Membrane Proteins ◽  
Outer Membrane ◽  
Outer Membrane Proteins ◽  
Mitochondrial Fusion ◽  
Intermembrane Space ◽  
Cell Biol

Mitofusins are outer membrane proteins essential for mitochondrial fusion. Their accepted topology posits that both N and C termini face the cytoplasm. In this issue, Mattie et al. (2018. J. Cell Biol. https://doi.org/10.1083/jcb.201611194) demonstrate instead that their C termini reside in the intermembrane space. These findings call for a revision of the current models of mitochondrial fusion.

scholarly journals Distribution and Apoptotic Function of Outer Membrane Proteins Depend on Mitochondrial Fusion

2014 ◽  
Vol 54 (5) ◽  
pp. 870-878 ◽  
Author(s):  
David Weaver ◽  
Verónica Eisner ◽  
Xingguo Liu ◽  
Péter Várnai ◽  
László Hunyady ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Outer Membrane ◽  
Outer Membrane Proteins ◽  
Mitochondrial Fusion

scholarly journals Structural Insight into Mitochondrial β-Barrel Outer Membrane Protein Biogenesis

2020 ◽  
Author(s):  
Kathryn A. Diederichs ◽  
Xiaodan Ni ◽  
Sarah E. Rollauer ◽  
Istvan Botos ◽  
Xiaofeng Tan ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Outer Membrane ◽  
Protein Import ◽  
Sequence Similarity ◽  
Outer Membrane Proteins ◽  
Complex Structure ◽  
Mitochondrial Outer Membrane ◽  
Intermembrane Space ◽  
Cytosolic Side ◽  
Lateral Gate

AbstractIn mitochondria, β-barrel outer membrane proteins mediate protein import, metabolite transport, lipid transport, and biogenesis. The Sorting and Assembly Machinery (SAM) complex consists of three proteins that assemble as a 1:1:1 complex to fold β-barrel proteins and insert them into the mitochondrial outer membrane. We report cryoEM structures of the SAM complex from Myceliophthora thermophila, which show that Sam50 forms a 16-stranded transmembrane β-barrel with a single polypeptide-transport-associated (POTRA) domain extending into the intermembrane space. Sam35 and Sam37 are located on the cytosolic side of the outer membrane, with Sam35 capping Sam50, and Sam37 interacting extensively with Sam35. Sam35 and Sam37 each adopt a GST-like fold, with no functional, structural, or sequence similarity to their bacterial counterparts. Structural analysis shows how the Sam50 β-barrel opens a lateral gate to accommodate its substrates. The SAM complex structure suggests how it interacts with other mitochondrial outer membrane proteins to create supercomplexes.

scholarly journals The Conservation of Low Complexity Regions in Bacterial Proteins Depends on the Pathogenicity of the Strain and Subcellular Location of the Protein

Genes ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 451
Author(s):  
Pablo Mier ◽  
Miguel A. Andrade-Navarro
Keyword(s):  
Membrane Proteins ◽  
Outer Membrane ◽  
Bacterial Species ◽  
Outer Membrane Proteins ◽  
Subcellular Location ◽  
Low Complexity ◽  
Extracellular Proteins ◽  
Bacterial Strains ◽  
Bacterial Proteins ◽  
Protein Subcellular Location

Low complexity regions (LCRs) in proteins are characterized by amino acid frequencies that differ from the average. These regions evolve faster and tend to be less conserved between homologs than globular domains. They are not common in bacteria, as compared to their prevalence in eukaryotes. Studying their conservation could help provide hypotheses about their function. To obtain the appropriate evolutionary focus for this rapidly evolving feature, here we study the conservation of LCRs in bacterial strains and compare their high variability to the closeness of the strains. For this, we selected 20 taxonomically diverse bacterial species and obtained the completely sequenced proteomes of two strains per species. We calculated all orthologous pairs for each of the 20 strain pairs. Per orthologous pair, we computed the conservation of two types of LCRs: compositionally biased regions (CBRs) and homorepeats (polyX). Our results show that, in bacteria, Q-rich CBRs are the most conserved, while A-rich CBRs and polyA are the most variable. LCRs have generally higher conservation when comparing pathogenic strains. However, this result depends on protein subcellular location: LCRs accumulate in extracellular and outer membrane proteins, with conservation increased in the extracellular proteins of pathogens, and decreased for polyX in the outer membrane proteins of pathogens. We conclude that these dependencies support the functional importance of LCRs in host–pathogen interactions.

scholarly journals Amikacin and bacteriophage treatment modulates outer membrane proteins composition in Proteus mirabilis biofilm

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Agnieszka Maszewska ◽  
Magdalena Moryl ◽  
Junli Wu ◽  
Bin Liu ◽  
Lu Feng ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Outer Membrane ◽  
Proteus Mirabilis ◽  
Protein Biosynthesis ◽  
Outer Membrane Proteins ◽  
Wild Strain ◽  
Elongation Factor ◽  
Resistance Mechanisms ◽  
Trna Synthetases ◽  
Cytoplasmic Proteins

AbstractModification of outer membrane proteins (OMPs) is the first line of Gram-negative bacteria defence against antimicrobials. Here we point to Proteus mirabilis OMPs and their role in antibiotic and phage resistance. Protein profiles of amikacin (AMKrsv), phage (Brsv) and amikacin/phage (AMK/Brsv) resistant variants of P. mirabilis were compared to that obtained for a wild strain. In resistant variants there were identified 14, 1, 5 overexpressed and 13, 5, 1 downregulated proteins for AMKrsv, Brsv and AMK/Brsv, respectively. Application of phages with amikacin led to reducing the number of up- and downregulated proteins compared to single antibiotic treatment. Proteins isolated in AMKrsv are involved in protein biosynthesis, transcription and signal transduction, which correspond to well-known mechanisms of bacteria resistance to aminoglycosides. In isolated OMPs several cytoplasmic proteins, important in antibiotic resistance, were identified, probably as a result of environmental stress, e.g. elongation factor Tu, asparaginyl-tRNA and aspartyl-tRNA synthetases. In Brsv there were identified: NusA and dynamin superfamily protein which could play a role in bacteriophage resistance. In the resistant variants proteins associated with resistance mechanisms occurring in biofilm, e.g. polyphosphate kinase, flagella basal body rod protein were detected. These results indicate proteins important in the development of P. mirabilis antibiofilm therapies.

scholarly journals Salt-responsive outer membrane proteins ofVibrio anguillarumserotype O1 as revealed by comparative proteome analysis

2009 ◽  
Vol 106 (6) ◽  
pp. 2079-2085 ◽  
Author(s):  
D.-Y. Kao ◽  
Y.-C. Cheng ◽  
T.-Y. Kuo ◽  
S.-B. Lin ◽  
C.-C. Lin ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Outer Membrane ◽  
Outer Membrane Proteins ◽  
Proteome Analysis
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