A water-soluble form of porin from the mitochondrial outer membrane of Neurospora crassa. Properties and relationship to the biosynthetic precursor form.

Pfaller, Rupert; Freitag, Helmut; Harmey, Matthew A.; Benz, Roland; Neupert, Walter

doi:10.1016/s0021-9258(17)39580-7

Cited by 97 publications

(33 citation statements)

References 36 publications

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“…Ws-porin inhibited the import of the biosynthetic porin precursor and of AAC (Fig. 1; also see Pfaller et al, 1985;Pfaller and Neupert, 1987). The import of Fe/S protein, F09, and Ft[i was also inhibited (Fig.…”

Section: Porin Competes For the Import Of Precursor Proteins Destined For Different Mitochondrial Compartmentsmentioning

confidence: 86%

“…Ws-porin was prepared as described previously (Pfaller et al, 1985;Pfaller and Neupert, 1987). SDS-PAGE (Laemmli, 1970) and fluorography (Chamberlain, 1979) were performed as described.…”

Section: Miscellaneousmentioning

confidence: 99%

“…Ws-porin, prepared from the purified membrane protein by denaturation/renaturation, has been found to have very similar binding and import properties compared to the biosynthetic porin precursor. This includes the requirement for a protease-sensitive site on the mitochondrial surface, competition with the biosynthetic porin precursor for binding, and two-step insertion into the outer membrane (Pfaller et al, 1985;Kleene et al, 1987;Pfaller and Neupert, 1987). Furthermore, ws-porin was able to form porin-specific membrane channels upon insertion into a lipid bilayer .…”

Section: Porin Competes For the Import Of Precursor Proteins Destined For Different Mitochondrial Compartmentsmentioning

confidence: 99%

“…2-4). Repeated freezing and thawing of ws-porin renders it largely incompetent for binding and import into mitochondria (Pfaller et al, 1985). Thus, it can be expected that ws-porin after freezing and thawing loses its ability to compete for the import of other precursors.…”

Section: Competition Requires the Native Form Of Porin Precursor Interacting With Binding Sites On The Outer Membranementioning

confidence: 99%

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Import pathways of precursor proteins into mitochondria: multiple receptor sites are followed by a common membrane insertion site.

Pfaller

Steger

Rassow

et al. 1988

The Journal of Cell Biology

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159

116

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Abstract, The precursor of porin, a mitochondrial outer membrane protein, competes for the import of precursors destined for the three other mitochondrial compartments, including the Fe/S protein of the bctcomplex (intermembrane space), the ADP/ATP carrier (inner membrane), subunit 9 of the F0-ATPase (inner membrane), and subunit 13 of the F,-ATPase (matrix). Competition occurs at the level of a common site at which precursors are inserted into the outer membrane. Protease-sensitive binding sites, which act before the common insertion site, appear to be responsible for the specificity and selectivity of mitochondrial protein uptake. We suggest that distinct receptor proteins on the mitochondrial surface specifically recognize precursor proteins and transfer them to a general insertion protein component (GIP) in the outer membrane. Beyond GIP, the import pathways diverge, either to the outer membrane or to translocation contact-sites, and then subsequently to the other mitochondrial compartments.

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Section: Porin Competes For the Import Of Precursor Proteins Destined For Different Mitochondrial Compartmentsmentioning

confidence: 86%

“…Ws-porin was prepared as described previously (Pfaller et al, 1985;Pfaller and Neupert, 1987). SDS-PAGE (Laemmli, 1970) and fluorography (Chamberlain, 1979) were performed as described.…”

Section: Miscellaneousmentioning

confidence: 99%

Section: Porin Competes For the Import Of Precursor Proteins Destined For Different Mitochondrial Compartmentsmentioning

confidence: 99%

Section: Competition Requires the Native Form Of Porin Precursor Interacting With Binding Sites On The Outer Membranementioning

confidence: 99%

See 2 more Smart Citations

Import pathways of precursor proteins into mitochondria: multiple receptor sites are followed by a common membrane insertion site.

Pfaller

Steger

Rassow

et al. 1988

The Journal of Cell Biology

Self Cite

159

116

View full text Add to dashboard Cite

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“…Helmut Freitag, a postdoc with a very original way of thinking, converted the detergentpurified Porin into a water-soluble form. Magically, this then indeed behaved like a precursor and could compete with Porin synthesized in a cell-free system for import into the outer membrane (16). Thus, we could use it to quantify receptor sites and determine affinities.…”

Section: Diversity Of Import Signals and Import Pathwaysmentioning

confidence: 99%

Untitled

2012

Annu. Rev. Biochem.

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Good fortune let me be an innocent child during World War II, a hopeful adolescent with encouraging parents during the years of German recovery, and a self-determined adult in a period of peace, freedom, and wealth. My luck continued as a scientist who could entirely follow his fancy. My mind was always set on understanding how things are made. At a certain point, I found myself confronted with the question of how mitochondria and organelles, which cannot be formed de novo, are put together. Intracellular transport of proteins, their translocation across the mitochondrial membranes, and their folding and assembly were the processes that fascinated me. Now, after some 30 years, we have wonderful insights, unimagined views of a complex and at the same time simple machinery and its workings. We have glimpses of how orderly processes are established in the cell to assemble from single molecules our beautiful mitochondria that every day make some 50 kg of ATP for each of us. At the same time, we have learned amazing lessons from the tinkering of evolution that developed mitochondria from bacteria.

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Mitochondrial Porins, Eukaryotic

Benz

2006

Encyclopedia of Molecular Cell Biology and Molecular Medicine

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A water-soluble form of porin from the mitochondrial outer membrane of Neurospora crassa. Properties and relationship to the biosynthetic precursor form.

Cited by 97 publications

References 36 publications

Import pathways of precursor proteins into mitochondria: multiple receptor sites are followed by a common membrane insertion site.

Import pathways of precursor proteins into mitochondria: multiple receptor sites are followed by a common membrane insertion site.

Untitled

Mitochondrial Porins, Eukaryotic

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