Summary: BAR domain

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BAR domain Edit Wikipedia article

BAR domain

Structure of amphiphysin BAR.^[1]

Identifiers

Symbol

BAR

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

BAR (Bin–Amphiphysin–Rvs) domains are highly conserved protein dimerisation domains that occur in many proteins involved in membrane dynamics in a cell. The BAR domain is banana shaped and binds to membrane via its concave face. It is capable of sensing membrane curvature by binding preferentially to curved membranes.

[edit] BAR domains occur in combinations with other domains

Many BAR family proteins contain alternative lipid specificity domains that help target these protein to particular membrane compartments. Some also have SH3 domains that bind to dynamin and thus proteins like amphiphysin and endophilin are implicated in the orchestration of vesicle scission.

[edit] N-BAR domain

Some BAR domain containing proteins have an N-terminal amphipathic helix preceding the BAR domain. This helix inserts (like in the epsin ENTH domain) into the membrane and induces curvature, which is stabilised by the BAR dimer. Amphiphysin, endophilin, BRAP1/bin2 and nadrin are examples of such proteins containing an N-BAR. The Drosophila amphiphysin N-BAR (DA-N-BAR) is an example of a protein with a preference for negatively charged surfaces.^[1]

[edit] F-BAR (EFC) domain

F-BAR domains (for FCH-BAR, or EFC for Extended FCH Homology) are BAR domains that are extensions of the already established FCH domain. They are frequently found at the amino terminus of proteins. They can bind lipid membranes and can tubulate lipids in vitro and in vivo, but their exact physiological role remains to be elucidated. Syndapin/pacsin proteins are an example of an F-BAR protein family.

[edit] Sorting nexins

The sorting nexin family of proteins includes several members that possess a BAR domain, including the well characterized SNX1 and SNX9.

[edit] Human proteins containing this domain

AMPH; ARHGAP17; BIN1; BIN2; BIN3; DNMBP; GMIP; RICH2; SH3BP1; SH3GL1; SH3GL2; SH3GL3; SH3GLB1; SH3GLB2;

[edit] See also

Epsin

Membrane curvature

[edit] External links

endocytosis.org

[edit] References

^ ^a ^b Peter BJ, Kent HM, Mills IG, et al. (January 2004). "BAR domains as sensors of membrane curvature: the amphiphysin BAR structure". Science 303 (5657): 495–9. doi:10.1126/science.1092586. PMID 14645856.

[edit] Publications

Leventis PA, Chow BM, Stewart BA, Iyengar B, Campos AR, Boulianne GL (November 2001). "Drosophila Amphiphysin is a post-synaptic protein required for normal locomotion but not endocytosis". Traffic 2 (11): 839–50. doi:10.1034/j.1600-0854.2001.21113.x. PMID 11733051. http://www.blackwell-synergy.com/openurl?genre=article&sid=nlm:pubmed&issn=1398-9219&date=2001&volume=2&issue=11&spage=839.
Zhang B, Zelhof AC (July 2002). "Amphiphysins: raising the BAR for synaptic vesicle recycling and membrane dynamics. Bin-Amphiphysin-Rvsp". Traffic 3 (7): 452–60. doi:10.1034/j.1600-0854.2002.30702.x. PMID 12047553. http://www.blackwell-synergy.com/openurl?genre=article&sid=nlm:pubmed&issn=1398-9219&date=2002&volume=3&issue=7&spage=452.Review.
Zelhof AC, Bao H, Hardy RW, Razzaq A, Zhang B, Doe CQ (December 2001). "Drosophila Amphiphysin is implicated in protein localization and membrane morphogenesis but not in synaptic vesicle endocytosis". Development 128 (24): 5005–15. PMID 11748137. http://dev.biologists.org/cgi/pmidlookup?view=long&pmid=11748137.
Mathew D, Popescu A, Budnik V (November 2003). "Drosophila amphiphysin functions during synaptic Fasciclin II membrane cycling". J. Neurosci. 23 (33): 10710–6. PMID 14627656. http://www.jneurosci.org/cgi/pmidlookup?view=long&pmid=14627656.
Peter BJ, Kent HM, Mills IG, et al. (January 2004). "BAR domains as sensors of membrane curvature: the amphiphysin BAR structure". Science 303 (5657): 495–9. doi:10.1126/science.1092586. PMID 14645856. http://www.sciencemag.org/cgi/pmidlookup?view=long&pmid=14645856.
Weissenhorn W (August 2005). "Crystal structure of the endophilin-A1 BAR domain". J. Mol. Biol. 351 (3): 653–61. doi:10.1016/j.jmb.2005.06.013. PMID 16023669. http://linkinghub.elsevier.com/retrieve/pii/S0022-2836(05)00658-3.
Gallop JL, Jao CC, Kent HM, et al. (June 2006). "Mechanism of endophilin N-BAR domain-mediated membrane curvature". EMBO J. 25 (12): 2898–910. doi:10.1038/sj.emboj.7601174. PMC 1500843. PMID 16763559. //www.ncbi.nlm.nih.gov/pmc/articles/PMC1500843/.
Masuda M, Takeda S, Sone M, et al. (June 2006). "Endophilin BAR domain drives membrane curvature by two newly identified structure-based mechanisms". EMBO J. 25 (12): 2889–97. doi:10.1038/sj.emboj.7601176. PMC 1500852. PMID 16763557. //www.ncbi.nlm.nih.gov/pmc/articles/PMC1500852/.
Frost A, Perera R, Roux A, et al. (March 2008). "Structural basis of membrane invagination by F-BAR domains". Cell 132 (5): 807–17. doi:10.1016/j.cell.2007.12.041. PMC 2384079. PMID 18329367. http://linkinghub.elsevier.com/retrieve/pii/S0092-8674(08)00131-1.

v t e Sorting nexins

SNX-BAR	SNX1 SNX2 SNX4 SNX5 SNX6 SNX7 SNX8 SNX9 SNX18 SNX30 SNX32 SNX33

SNX-PX	SNX3 SNX10 SNX11 SNX12 SNX16 SNX20 SNX21 SNX22 SNX24 SNX29

SNX-Other	SNX13 SNX14 SNX15 SNX17 SNX19 SNX23 SNX25 SNX26 SNX27 SNX28 SNX31

Related articles	PX domain BAR domain Retromer

B bsyn: dna (repl, cycl, reco, repr) · tscr (fact, tcrg, nucl, rnat, rept, ptts) · tltn (risu, pttl, nexn) · dnab, rnab/runp · stru (domn, 1°, 2°, 3°, 4°)

v t e Protein domains

BAR BIR BZIP CARD C1 C2 DED ENTH FYVE HEAT Kringle LIM LRR NACHT PAS PDZ Pyrin PH PX SH2 SH3 SUN TRIO WD40 zinc finger

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BAR domain Provide feedback

BAR domains are dimerisation, lipid binding and curvature sensing modules found in many different protein families. A BAR domain with an additional N-terminal amphipathic helix (an N-BAR) can drive membrane curvature. These N-BAR domains are found in amphiphysin, endophilin, BRAP and Nadrin. BAR domains are also frequently found alongside domains that determine lipid specificity, like PF00169 and PF00787 domains in beta centaurins and sorting nexins respectively.

Literature references

Gallop JL, Butler PJ, McMahon HT; , Nature. 2005;438:675-678.: Endophilin and CtBP/BARS are not acyl transferases in endocytosis or Golgi fission. PUBMED:16319893 EPMC:16319893
Peter BJ, Kent HM, Mills IG, Vallis Y, Butler PJ, Evans PR, McMahon HT; , Science. 2004;303:495-499.: BAR domains as sensors of membrane curvature: the amphiphysin BAR structure. PUBMED:14645856 EPMC:14645856
Gallop JL, Jao CC, Kent HM, Butler PJ, Evans PR, Langen R, McMahon HT; , EMBO J. 2006;25:2898-2910.: Mechanism of endophilin N-BAR domain-mediated membrane curvature. PUBMED:16763559 EPMC:16763559
Weissenhorn W; , J Mol Biol. 2005;351:653-661.: Crystal structure of the endophilin-A1 BAR domain. PUBMED:16023669 EPMC:16023669

Internal database links

Similarity to PfamA using HHSearch:

Arfaptin Vps5 BAR_2

External database links

PANDIT:	PF03114
Pseudofam:	PF03114
SCOP:	1uru
SYSTERS:	BAR

This tab holds annotation information from the InterPro database.

InterPro entry IPR004148

Endocytosis and intracellular transport involve several mechanistic steps:

(1) for the internalisation of cargo molecules, the membrane needs to bend to form a vesicular structure, which requires membrane curvature and a rearrangement of the cytoskeleton;
(2) following its formation, the vesicle has to be pinched off the membrane;
(3) the cargo has to be subsequently transported through the cell and the vesicle must fuse with the correct cellular compartment.

Members of the Amphiphysin protein family are key regulators in the early steps of endocytosis, involved in the formation of clathrin-coated vesicles by promoting the assembly of a protein complex at the plasma membrane and directly assist in the induction of the high curvature of the membrane at the neck of the vesicle. Amphiphysins contain a characteristic domain, known as the BAR (Bin-Amphiphysin-Rvs)-domain, which is required for their in vivo function and their ability to tubulate membranes [PUBMED:14993925].

The crystal structure of these proteins suggest the domain forms a crescent-shaped dimer of a three-helix coiled coil with a characteristic set of conserved hydrophobic, aromatic and hydrophilic amino acids. Proteins containing this domain have been shown to homodimerise, heterodimerise or, in a few cases, interact with small GTPases.

Gene Ontology

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

Cellular component	cytoplasm (GO:0005737)
Molecular function	protein binding (GO:0005515)

Domain organisation

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

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Pfam Clan

This family is a member of clan Golgi-transport (CL0145), which contains the following 9 members:

Arfaptin BAR BAR_2 BAR_3_WASP_bdg FAM92 IMD Pil1 Sec34 Vps5

Alignments

We store a range of different sequence alignments for families. As well as the seed alignment from which the family is built, we provide the full alignment, generated by searching the sequence database using the family HMM. We also generate alignments using four representative proteomes (RP) sets, the NCBI sequence database, and our metagenomics sequence database. More...

There are various ways to view or download the sequence alignments that we store. We provide several sequence viewers and a plain-text Stockholm-format file for download.

Alignment types

We make a range of alignments for each Pfam-A family:

seed: the curated alignment from which the HMM for the family is built
full: the alignment generated by searching the sequence database using the HMM
RP15/RP35/RP55/RP75: Representative Proteomes (RPs) at 15%, 35%, 55% and 75% co-membership thresholds
NCBI: alignment generated by searching the NCBI sequence database using the family HMM
meta: alignment generated by searching the metagenomics sequence database using the family HMM

Viewing

You can see the alignments as HTML or in three different sequence viewers:

jalview: a Java applet developed at the University of Dundee. You will need Java installed before running jalview
HTML: an HTML page showing the whole alignment.Please note: full Pfam alignments can be very large. These HTML views are extremely large and often cause problems for browsers. Please use either jalview or the Pfam viewer if you have trouble viewing the HTML version
PP/Heatmap: an HTML-based representation of the alignment, coloured according to the posterior-probability (PP) values from the HMM. As for the standard HTML view, heatmap alignments can also be very large and slow to render.
Pfam viewer: an HTML-based viewer that uses DAS to retrieve alignment fragments on request

Reformatting

You can download (or view in your browser) a text representation of a Pfam alignment in various formats:

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You can also change the order in which sequences are listed in the alignment, change how insertions are represented, alter the characters that are used to represent gaps in sequences and, finally, choose whether to download the alignment or to view it in your browser directly.

Downloading

You may find that large alignments cause problems for the viewers and the reformatting tool, so we also provide all alignments in Stockholm format. You can download either the plain text alignment, or a gzipped version of it.

View options

We make a range of alignments for each Pfam-A family. You can see a description of each above. You can view these alignments in various ways but please note that some types of alignment are never generated while others may not be available for all families, most commonly because the alignments are too large to handle.

	Seed (28)	Full (2173)	Representative proteomes				NCBI (2310)	Meta (1)
	Seed (28)	Full (2173)	RP15 (333)	RP35 (558)	RP55 (919)	RP75 (1287)	NCBI (2310)	Meta (1)
Jalview	View	View	View	View	View	View	View	View
HTML	View	View	View	View	View	View
PP/heatmap	₁	View	View	View	View	View
Pfam viewer	View	View

¹Cannot generate PP/Heatmap alignments for seeds; no PP data available

Key: available, not generated, — not available.

Format an alignment

	Seed (28)	Full (2173)	Representative proteomes				NCBI (2310)	Meta (1)
	Seed (28)	Full (2173)	RP15 (333)	RP35 (558)	RP55 (919)	RP75 (1287)	NCBI (2310)	Meta (1)
Alignment:
Format:
Order:	Tree Alphabetical
Sequence:	Inserts lower case All upper case
Gaps:
Download/view:	Download View

Download options

We make all of our alignments available in Stockholm format. You can download them here as raw, plain text files or as gzip-compressed files.

	Seed (28)	Full (2173)	Representative proteomes				NCBI (2310)	Meta (1)
	Seed (28)	Full (2173)	RP15 (333)	RP35 (558)	RP55 (919)	RP75 (1287)	NCBI (2310)	Meta (1)
Raw Stockholm	Download	Download	Download	Download	Download	Download	Download	Download
Gzipped	Download	Download	Download	Download	Download	Download	Download	Download

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

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's seed alignment. 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 alignment.

Note: You can also download the data file for the tree.

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:

Psi-blast P25343

Previous IDs:

none

Type:

Domain

Author:

Bateman A, McMahon HT

Number in seed:

28

Number in full:

2173

Average length of the domain:

214.10 aa

Average identity of full alignment:

18 %

Average coverage of the sequence by the domain:

40.80 %

HMM information

HMM build commands:

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

search method: hmmsearch -Z 23193494 -E 1000 --cpu 4 HMM pfamseq

Model details:

Parameter	Sequence	Domain
Gathering cut-off	24.5	24.5
Trusted cut-off	24.5	24.5
Noise cut-off	24.4	24.4

Model length:

230

Family (HMM) version:

13

Download:

download the raw HMM for this family

Species distribution

Sunburst
Tree

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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. 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, its 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.

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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:

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Interactions

There is 1 interaction for this family. More...

BAR

Structures

For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the BAR domain has been found. There are 19 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein seqence.

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Archea	Eukaryota
Bacteria	Other sequences
Viruses	Unclassified
Viroids	Unclassified sequence

Family: BAR (PF03114)

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