Summary: Eukaryotic porin

Pfam includes annotations and additional family information from a range of different sources. These sources can be accessed via the tabs below.

Wikipedia: Voltage-dependent anion channel
Pfam
InterPro

This is the Wikipedia entry entitled "Voltage-dependent anion channel". More...

The Wikipedia text that you see displayed here is a download from Wikipedia. This means that the information we display is a copy of the information from the Wikipedia database. The button next to the article title ("Edit Wikipedia article") takes you to the edit page for the article directly within Wikipedia. You should be aware you are not editing our local copy of this information. Any changes that you make to the Wikipedia article will not be displayed here until we next download the article from Wikipedia. We currently download new content on a nightly basis.

Does Pfam agree with the content of the Wikipedia entry ?

Pfam has chosen to link families to Wikipedia articles. In some case we have created or edited these articles but in many other cases we have not made any direct contribution to the content of the article. The Wikipedia community does monitor edits to try to ensure that (a) the quality of article annotation increases, and (b) vandalism is very quickly dealt with. However, we would like to emphasise that Pfam does not curate the Wikipedia entries and we cannot guarantee the accuracy of the information on the Wikipedia page.

Editing Wikipedia articles

Before you edit for the first time

Wikipedia is a free, online encyclopedia. Although anyone can edit or contribute to an article, Wikipedia has some strong editing guidelines and policies, which promote the Wikipedia standard of style and etiquette. Your edits and contributions are more likely to be accepted (and remain) if they are in accordance with this policy.

You should take a few minutes to view the following pages:

How your contribution will be recorded

Anyone can edit a Wikipedia entry. You can do this either as a new user or you can register with Wikipedia and log on. When you click on the "Edit Wikipedia article" button, your browser will direct you to the edit page for this entry in Wikipedia. If you are a registered user and currently logged in, your changes will be recorded under your Wikipedia user name. However, if you are not a registered user or are not logged on, your changes will be logged under your computer's IP address. This has two main implications. Firstly, as a registered Wikipedia user your edits are more likely seen as valuable contribution (although all edits are open to community scrutiny regardless). Secondly, if you edit under an IP address you may be sharing this IP address with other users. If your IP address has previously been blocked (due to being flagged as a source of 'vandalism') your edits will also be blocked. You can find more information on this and creating a user account at Wikipedia.

If you have problems editing a particular page, contact us at pfam-help@sanger.ac.uk and we will try to help.

Contact us

The community annotation is a new facility of the Pfam web site. If you have problems editing or experience problems with these pages please contact us.

Voltage-dependent anion channel

Eukaryotic porin

Identifiers

Symbol

Porin_3

Available protein structures:
Pfam	structures
PDB	RCSB PDB; PDBe
PDBsum	structure summary

Voltage-dependent anion channels are a class of porin ion channel located on the outer mitochondrial membrane.^[1]

This major protein of the outer mitochondrial membrane of eukaryotes. It forms a voltage-dependent anion-selective channel (VDAC) that behaves as a general diffusion pore for small hydrophilic molecules.^[2]^[3]^[4]^[5] The channel adopts an open conformation at low or zero membrane potential and a closed conformation at potentials above 30-40 mV. VDAC facilitates the exchange of ions and molecules between mitochondria and cytosol and is regulated by the interactions with other proteins and small molecules.^[6]

[edit] Structure

This protein contains about 280 amino acids and its sequence is composed of between 12 to 16 beta-strands that span the mitochondrial outer membrane.^[7]

Since its discovery in 1976, extensive function and structure analysis of VDAC proteins has been conducted. A prominent feature of the pore emerged: when reconstituted into planar lipid bilayers, there is a voltage-dependent switch between an anion-selective high-conductance state with high metabolite flux and a cation-selective low-conductance state with limited passage of metabolites.

More than 30 years after its initial discovery, in 2008, three independent structural projects of VDAC-1 were completed. The first was solved by multi-dimensional NMR spectroscopy. The second applied a hybrid approach using crystallographic data. The third was for mouse VDAC-1 crystals determined by X-ray crystallographic techniques. The three projects of the 3D structures of VDAC-1 revealed many structural features. First, VDAC-1 represents a new structural class of outer membrane β-barrel proteins with an odd number of strands. Another aspect is that the negatively charged side chain of residue E73 is oriented towards the hydrophobic membrane environment. The 19-stranded 3D structure obtained under different experimental sources by three different laboratories fits the EM and AFM data from native membrane sources and represents a biologically relevant state of VDAC-1.^[6]

[edit] Examples

Yeast contains two members of this family (genes POR1 and POR2); vertebrates have at least three members (genes VDAC1, VDAC2 and VDAC3).^[7]

Human proteins containing this domain include TOMM40, TOMM40L, VDAC1, VDAC2, and VDAC3.

[edit] References

^ Hoogenboom BW, Suda K, Engel A, Fotiadis D (2007). "The supramolecular assemblies of voltage-dependent anion channels in the native membrane". J. Mol. Biol. 370 (2): 246–55. doi:10.1016/j.jmb.2007.04.073. PMID 17524423.
^ Benz R (1994). "Permeation of hydrophilic solutes through mitochondrial outer membranes: review on mitochondrial porins". Biochim. Biophys. Acta 1197 (2): 167–196. PMID 8031826.
^ Mannella CA (1992). "The 'ins' and 'outs' of mitochondrial membrane channels". Trends Biochem. Sci. 17 (8): 315–320. doi:10.1016/0968-0004(92)90444-E. PMID 1384178.
^ Dihanich M (1990). "The biogenesis and function of eukaryotic porins". Experientia 46 (2): 146–153. doi:10.1007/BF02027310. PMID 1689252.
^ Forte M, Guy HR, Mannella CA (1987). "Molecular genetics of the VDAC ion channel: structural model and sequence analysis". J. Bioenerg. Biomembr. 19 (4): 341–350. doi:10.1007/BF00768537. PMID 2442148.
^ ^a ^b Hiller S, Abramson J, Mannella C, Wagner G, Zeth K (September 2010). "The 3D structures of VDAC represent a native conformation". Trends Biochem. Sci. 35 (9): 514–21. doi:10.1016/j.tibs.2010.03.005. PMC 2933295. PMID 20708406. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2933295.
^ ^a ^b Sampson MJ, Lovell RS, Davison DB, Craigen WJ (1996). "A novel mouse mitochondrial voltage-dependent anion channel gene localizes to chromosome 8". Genomics 36 (1): 192–196. doi:10.1006/geno.1996.0445. PMID 8812436.

[edit] External links

MeSH Voltage-Dependent+Anion+Channels

This membrane protein-related article is a stub. You can help Wikipedia by expanding it.

Membrane transport protein: ion channels (TC 1A)

Ca²⁺: Calcium channel

Voltage-gated	L-type/Ca_vα (1.1, 1.2, 1.3, 1.4) · N-type/Ca_vα2.2 · P-type/Ca_vα(2.1) · Q-type/Ca_vα2.1 · R-type/Ca_vα2.3 · T-type/Ca_vα(3.1, 3.2, 3.3) α₂δ-subunits (1, 2) · β-subunits (β1, β2, β3, β4) · γ-subunits (γ1, γ2, γ3, γ4) Cation channels of sperm (1, 2, 3, 4) · Two-pore channel (1, 2)

Ligand-gated	Inositol trisphosphate receptor (1, 2, 3) · Ryanodine receptor (1, 2, 3)

Na⁺: Sodium channel

Constitutively active	Epithelial sodium channel (α, β, γ, δ)

Proton gated	Amiloride-sensitive cation channel (1, 2, 3, 4)

Voltage-gated	Na_vα (1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 7A) · Na_vβ (1, 2, 3, 4)

K⁺: Potassium channel

Voltage-gated	K_vα1-6 (1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8) · (2.1, 2.2) · (3.1, 3.2, 3.3, 3.4) · (4.1, 4.2, 4.3) · (5.1) · (6.1, 6.2, 6.3, 6.4) K_vα7-12 (7.1, 7.2, 7.3, 7.4, 7.5) · (8.1, 8.2) · (9.1, 9.2, 9.3) · (10.1, 10.2) · (11.1/hERG, 11.2, 11.3) · (12.1, 12.2, 12.3) K_vβ (1, 2, 3) · KCNIP (1, 2, 3, 4) · minK/ISK · minK/ISK-like · MiRP (1, 2, 3) · Shaker gene

Calcium-activated	BK channel (α1, β1, β2, β3, β4) · SK channel (SK1, SK2, SK3) · IK channel (IK1) · K_Ca (1.1, 2.1, 2.2, 2.3, 3.1, 4.1, 4.2, 5.1)

Inward-rectifier	K_ATP · K_ir (1.1, 2.1, 2.2, 2.3, 2.4, 2.6) · GIRK/K_ir (3.1, 3.2, 3.3, 3.4) · K_ir (4.1, 4.2, 5.1, 6.1, 6.2, 7.1)

Tandem pore domain	K2P (1, 2, 3, 4, 5, 6, 7, 9, 10, 12, 13, 15, 16, 17, 18)

Other

Cl^-: Chloride channel	ANO1 · Bestrophin (1, 2) · CFTR · CLCA (1, 2, 3, 4) · CLCN (1, 2, 3, 4, 5, 6, 7, KA, KB) · CLIC (1, 2, 3, 4, 5, 6, L1) · CLNS (1A, 1B)

H⁺: Voltage-gated	HVCN1

M⁺: TRP cation channel	TRPA (1) · TRPC (1, 2, 3, 4, 4AP, 5, 6, 7) · TRPM (1, 2, 3, 4, 5, 6, 7, 8) · TRPML (1, 2, 3) · TRPN · TRPP (1, 2) · TRPV (1, 2, 3, 4, 5, 6)

Cyclic nucleotide-gated (FC)	α (1, 2, 3, 4) · β (1, 2, 3) · HCN (1, 2, 3, 4)

Porin	Aquaporin (0, 1, 2, 3, 4, 5, 6, 7, 8, 9) · Voltage-dependent anion channel (1, 2, 3) · General bacterial porin family

Gap junction	Connexin: A (GJA1, GJA3, GJA4, GJA5, GJA8, GJA9, GJA10) · B (GJB1, GJB2, GJB3, GJB4, GJB5, GJB6, GJB7) · C (GJC1, GJC2, GJC3) · D (GJD2, GJD3, GJD4)) Innexin

General	Ligand-gated ion channel · Voltage-gated ion channel · Stretch-activated ion channel

see also disorders
B memb: cead, trns (1A, 1C, 1F, 2A, 3A1, 3A2-3, 3D), othr

This article incorporates text from the public domain Pfam and InterPro IPR001925

This page is based on a Wikipedia article. The text is available under the Creative Commons Attribution/Share-Alike License.

This tab holds the annotation information that is stored in the Pfam database. As we move to using Wikipedia as our main source of annotation, the contents of this tab will be gradually replaced by the Wikipedia tab.

Eukaryotic porin

No Pfam abstract.

External database links

PANDIT:	PF01459
PROSITE:	PDOC00483
Pseudofam:	PF01459
SYSTERS:	Porin_3
Transporter classification:	1.B.8 3.A.8

This tab holds annotation information from the InterPro database.

InterPro entry IPR001925

The major protein of the outer mitochondrial membrane of eukaryotes is a porin that forms a voltage-dependent anion-selective channel (VDAC) that behaves as a general diffusion pore for small hydrophilic molecules [PUBMED:8031826, PUBMED:1384178, PUBMED:1689252, PUBMED:2442148]. The channel adopts an open conformation at low or zero membrane potential and a closed conformation at potentials above 30-40 mV.

This protein contains about 280 amino acids and its sequence is composed of between 12 to 16 beta-strands that span the mitochondrial outer membrane. Yeast contains two members of this family (genes POR1 and POR2); vertebrates have at least three members (genes VDAC1, VDAC2 and VDAC3) [PUBMED:8812436].

Gene Ontology

The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.

Cellular component	mitochondrial outer membrane (GO:0005741)
Molecular function	voltage-gated anion channel activity (GO:0008308)
Biological process	anion transport (GO:0006820)
	transmembrane transport (GO:0055085)
	regulation of anion transport (GO:0044070)

Domain organisation

Below is a listing of the unique domain organisations or architectures in which this domain is found. More...

Loading domain graphics...

Alignments

There are various ways to view or download the sequence alignments that we store. You can use a sequence viewer to look at either the seed or full alignment for the family, or you can look at a plain text version of the sequence in a variety of different formats. More...

View options

Alignment:	Seed (92) Full (859) NCBI (967) Metagenomics (9)
Viewer:

Formatting options

Alignment:	Seed (92) Full (859)
Format:
Order:	Tree Alphabetical
Sequence:	Inserts lower case All upper case
Gaps:
Download/view:	Download View

Download options

Very large alignments can often cause problems for the formatting tool above. If you find that downloading or viewing a large alignment is problematic, you can also download a gzip-compressed, Stockholm-format file containing the seed or full alignment for this family.

You can also download a FASTA format file containing the full-length sequences for all sequences in the full alignment.

The main seed and full alignments are generated using sequences from the UniProt sequence database. However, we also generate alignments using sequences from the NCBI sequence database and the "metaseq" metagenomics dataset.

You can view alignments from these two additional datasets using the form above, or you can download alignments of NCBI or metagenomics sequences, as gzip-compressed files.

Pfam alignments:	Seed (92) Full (859) NCBI (967) Metagenomics (9)
Full length sequences	Full-sequences (859)

External links

MyHits provides a collection of tools to handle multiple sequence alignments. For example, one can refine a seed alignment (sequence addition or removal, re-alignment or manual edition) and then search databases for remote homologs using HMMER3.

HMM logo

HMM logos is one way of visualising profile HMMs. Logos provide a quick overview of the properties of an HMM in a graphical form. You can see a more detailed description of HMM logos and find out how you can interpret them here. More...

Trees

This page displays the phylogenetic tree for this family. We use FastTree to calculate neighbour join trees with a local bootstrap based on 100 resamples (shown next to the tree nodes). FastTree calculates approximately-maximum-likelihood phylogenetic trees from our seed or full alignments.

Note: You can also download the data files for the seed, full, NCBI or metagenomics trees.

Curation and family details

This section shows the detailed information about the Pfam family. You can see the definitions of many of the terms in this section in the glossary and a fuller explanation of the scoring system that we use in the scores section of the help pages.

Curation

Seed source:

Prodom_3211 (release 99.1) & Pfam-B__3211 (release 7.5)

Previous IDs:

Euk_porin;

Type:

Family

Author:

Bateman A

Number in seed:

92

Number in full:

859

Average length of the domain:

254.50 aa

Average identity of full alignment:

22 %

Average coverage of the sequence by the domain:

86.69 %

HMM information

HMM build commands:

build method: hmmbuild -o /dev/null HMM SEED

search method: hmmsearch -Z 15929002 -E 1000 --cpu 4 HMM pfamseq

Model details:

Parameter	Sequence	Domain
Gathering cut-off	26.7	26.7
Trusted cut-off	26.9	26.8
Noise cut-off	26.6	26.6

Model length:

273

Family (HMM) version:

17

Download:

download the raw HMM for this family

Species distribution

Sunburst
Tree

Sunburst controls

Hide

Weight segments by...

number of sequences
number of species

Change the size of the sunburst

Small

Large

Colour assignments

Archea	Eukaryota
Bacteria	Other sequences
Viruses	Unclassified
Viroids	Unclassified sequence

This visualisation provides a simple graphical representation of the distribution of this family across species. You can find the original interactive tree in the adjacent tab if you need to select sub-trees and view sequence alignments. More...

This chart is a modified "sunburst" visualisation of the species tree for this family. It shows each node in the tree as a separate arc, arranged radially with the superkingdoms at the centre and the species arrayed around the outermost ring.

How the sunburst is generated

The tree is built by considering the taxonomic lineage of each sequence that has a match to this family. For each node in the resulting tree, we draw an arc in the sunburst. The radius of the arc, it's distance from the root node at the centre of the sunburst, shows the taxonomic level ("superkingdom", "kingdom", etc). The length of the arc represents either the number of sequences represented at a given level, or the number of species that are found beneath the node in the tree. The weighting scheme can be changed using the sunburst controls.

In order to reduce the complexity of the representation, we reduce the number of taxonomic levels that we show. We consider only the following eight major taxonomic levels:

superkingdom
kingdom
phylum
class
order
family
genus
species

Colouring and labels

Segments of the tree are coloured approximately according to their superkingdom. For example, archeal branches are coloured with shades of orange, eukaryotes in shades of purple, etc. The colour assignments are shown under the sunburst controls. Where space allows, the name of the taxonomic level will be written on the arc itself.

As you move your mouse across the sunburst, the current node will be highlighted. In the top section of the controls panel we show a summary of the lineage of the currently highlighed node. If you pause over an arc, a tooltip will be shown, giving the name of the taxonomic level in the title and a summary of the number of sequences and species below that node in the tree.

Anomalies in the taxonomy tree

There are some situations that the sunburst tree cannot easily handle and for which we have work-arounds in place.

Missing taxonomic levels

Some species in the taxonomic tree may not have one or more of the main eight levels that we display. For example, Bos taurus is not assigned an order in the NCBI taxonomic tree. In such cases we mark the omitted level with, for example, "No order", in both the tooltip and the lineage summary.

Unmapped species names

The tree is built by looking at each sequence in the full alignment for the family. We take the name of the species given by UniProt and try to map that to the full taxonomic tree from NCBI. In some cases, the name chosen by UniProt does not map to any node in the NCBI tree, perhaps because the chosen name is listed as a synonym or a misspelling in the NCBI taxonomy.

So that these nodes are not simply omitted from the sunburst tree, we group them together in a separate branch (or segment of the sunburst tree). Since we cannot determine the lineage for these unmapped species, we show all levels between the superkingdom and the species as "uncategorised".

Sub-species

Since we reduce the species tree to only the eight main taxonomic levels, sequences that are mapped to the sub-species level in the tree would not normally be shown. Rather than leave out these species, we map them instead to their parent species. So, for example, for sequences belonging to one of the Vibrio cholerae sub-species in the NCBI taxonomy, we show them instead as belonging to the species Vibrio cholerae.

Too many species/sequences

For large species trees, you may see blank regions in the outer layers of the sunburst. These occur when there are large numbers of arcs to be drawn in a small space. If an arc is less than approximately one pixel wide, it will not be drawn and the space will be left blank. You may still be able to get some information about the species in that region by moving your mouse across the area, but since each arc will be very small, it will be difficult to accurately locate a particular species.

Tree controls

Hide

The tree shows the occurrence of this domain across different species. More...

Species trees

We show the species tree in one of two ways. For smaller trees we try to show an interactive representation, which allows you to select specific nodes in the tree and view them as an alignment or as a set of Pfam domain graphics.

Unfortunately we have found that there are problems viewing the interactive tree when the it becomes larger than a certain limit. Furthermore, we have found that Internet Explorer can become unresponsive when viewing some trees, regardless of their size. We therefore show a text representation of the species tree when the size is above a certain limit or if you are using Internet Explorer to view the site.

If you are using IE you can still load the interactive tree by clicking the "Generate interactive tree" button, but please be aware of the potential problems that the interactive species tree can cause.

Interactive tree

For all of the domain matches in a full alignment, we count the number that are found on all sequences in the alignment. This total is shown in the purple box.

We also count the number of unique sequences on which each domain is found, which is shown in green. Note that a domain may appear multiple times on the same sequence, leading to the difference between these two numbers.

Finally, we group sequences from the same organism according to the NCBI code that is assigned by UniProt, allowing us to count the number of distinct sequences on which the domain is found. This value is shown in the pink boxes.

We use the NCBI species tree to group organisms according to their taxonomy and this forms the structure of the displayed tree. Note that in some cases the trees are too large (have too many nodes) to allow us to build an interactive tree, but in most cases you can still view the tree in a plain text, non-interactive representation. Those species which are represented in the seed alignment for this domain are highlighted.

You can use the tree controls to manipulate how the interactive tree is displayed:

show/hide the summary boxes
highlight species that are represented in the seed alignment
expand/collapse the tree or expand it to a given depth
select a sub-tree or a set of species within the tree and view them graphically or as an alignment
save a plain text representation of the tree

Loading...

Please note: for large trees this can take some time. While the tree is loading, you can safely switch away from this tab but if you browse away from the family page entirely, the tree will not be loaded.

Family: Porin_3 (PF01459)

Jump to...

Summary: Eukaryotic porin

Does Pfam agree with the content of the Wikipedia entry ?

Editing Wikipedia articles

Before you edit for the first time

How your contribution will be recorded

Contact us

Voltage-dependent anion channel

Contents

[edit] Structure

[edit] Examples

[edit] References

[edit] External links

Eukaryotic porin

External database links

InterPro entry IPR001925

Gene Ontology

Domain organisation

Alignments

Viewing

Downloading

View options

Formatting options

Download options

External links

HMM logo

Trees

Curation and family details

Curation

HMM information

Species distribution

Sunburst controls

Weight segments by...

Change the size of the sunburst

Colour assignments

How the sunburst is generated

Colouring and labels

Anomalies in the taxonomy tree

Missing taxonomic levels

Unmapped species names

Sub-species

Too many species/sequences

Tree controls

Annotation

Download tree

Selected sequences

Species trees

Interactive tree