Please note: this site relies heavily on the use of javascript. Without a javascript-enabled browser, this site will not function correctly. Please enable javascript and reload the page, or switch to a different browser.
0  structures 868  species 0  interactions 1505  sequences 168  architectures

Family: TAT_signal (PF10518)

Summary: TAT (twin-arginine translocation) pathway signal sequence

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

The Pfam group coordinates the annotation of Pfam families in Wikipedia, but we have not yet assigned a Wikipedia article to this family. If you think that a particular Wikipedia article provides good annotation, please let us know.

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.

TAT (twin-arginine translocation) pathway signal sequence Provide feedback

No Pfam abstract.

Literature references

  1. Berks BC; , Mol Microbiol. 1996;22:393-404.: A common export pathway for proteins binding complex redox cofactors?. PUBMED:8939424 EPMC:8939424


Internal database links

External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR019546

The twin-arginine translocation (Tat) pathway serves the role of transporting folded proteins across energy-transducing membranes [PUBMED:16322447]. Homologues of the genes that encode the transport apparatus occur in archaea, bacteria, chloroplasts, and plant mitochondria [PUBMED:12029389]. In bacteria, the Tat pathway catalyses the export of proteins from the cytoplasm across the inner/cytoplasmic membrane. In chloroplasts, the Tat components are found in the thylakoid membrane and direct the import of proteins from the stroma. The Tat pathway acts separately from the general secretory (Sec) pathway, which transports proteins in an unfolded state [PUBMED:16092521].

It is generally accepted that the primary role of the Tat system is to translocate fully folded proteins across membranes. An example of proteins that need to be exported in their 3D conformation are redox proteins that have acquired complex multi-atom cofactors in the bacterial cytoplasm (or the chloroplast stroma or mitochondrial matrix). They include hydrogenases, formate dehydrogenases, nitrate reductases, trimethylamine N-oxide (TMAO) reductases and dimethyl sulphoxide (DMSO) reductases [PUBMED:16756481, PUBMED:15546663]. The Tat system can also export whole heteroligomeric complexes in which some proteins have no Tat signal. This is the case of the DMSO reductase or formate dehydrogenase complexes. But there are also other cases where the physiological rationale for targeting a protein to the Tat signal is less obvious. Indeed, there are examples of homologous proteins that are in some cases targeted to the Tat pathway and in other cases to the Sec apparatus. Some examples are: copper nitrite reductases, flavin domains of flavocytochrome c and N-acetylmuramoyl-L-alanine amidases [PUBMED:15802249].

In halophilic archaea such as Halobacterium almost all secreted proteins appear to be Tat targeted. It has been proposed to be a response to the difficulties these organisms would otherwise face in successfully folding proteins extracellularly at high ionic strength [PUBMED:12427925].

The Tat signal peptide consists of three motifs: the positively charged N-terminal motif, the hydrophobic region and the C-terminal region that generally ends with a consensus short motif (A-x-A) specifying cleavage by signal peptidase. Sequence analysis revealed that signal peptides capable of targeting the Tat protein contain the consensus sequence [ST]-R-R-x-F-L-K. The nearly invariant twin-arginine gave rise to the pathway's name. In addition the h-region of Tat signal peptides is typically less hydrophobic than that of Sec-specific signal peptides [PUBMED:16756481, PUBMED:15546663].

Domain organisation

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

Loading domain graphics...

Pfam Clan

This family is a member of clan TAT (CL0300), which has the following description:

This motif is found in a wide range of secreted proteins. It is named after the conserved pair of arginines that is followed by a hydrophobic stretch.

The clan contains the following 2 members:

TAT_signal UCR_Fe-S_N

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...

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
(64)
Full
(1505)
Representative proteomes NCBI
(1326)
Meta
(535)
RP15
(160)
RP35
(342)
RP55
(422)
RP75
(484)
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, x not generated, not available.

Format an alignment

  Seed
(64)
Full
(1505)
Representative proteomes NCBI
(1326)
Meta
(535)
RP15
(160)
RP35
(342)
RP55
(422)
RP75
(484)
Alignment:
Format:
Order:
Sequence:
Gaps:
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
(64)
Full
(1505)
Representative proteomes NCBI
(1326)
Meta
(535)
RP15
(160)
RP35
(342)
RP55
(422)
RP75
(484)
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 View help on the curation process

Seed source: Bateman A
Previous IDs: none
Type: Motif
Author: Bateman A
Number in seed: 64
Number in full: 1505
Average length of the domain: 25.60 aa
Average identity of full alignment: 34 %
Average coverage of the sequence by the domain: 5.54 %

HMM information View help on HMM parameters

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 19.9 19.9
Trusted cut-off 19.9 19.9
Noise cut-off 19.8 19.8
Model length: 26
Family (HMM) version: 4
Download: download the raw HMM for this family

Species distribution

Sunburst controls

Show

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...

Loading sunburst data...

Tree controls

Hide

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

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.