Summary

Ubiquitin-conjugating enzyme

Proteins destined for proteasome-mediated degradation may be ubiquitinated. Ubiquitination follows conjugation of ubiquitin to a conserved cysteine residue of UBC homologues. TSG101 is one of several UBC homologues that lacks this active site cysteine [4, 5].

Literature references

Cook WJ, Jeffrey LC, Sullivan ML, Vierstra RD; , J Biol Chem 1992;267:15116-15121.: Three-dimensional structure of a ubiquitin-conjugating enzyme (E2). PUBMED:1321826
Cook WJ, Jeffrey LC, Xu Y, Chau V; , Biochemistry 1993;32:13809-13817.: Tertiary structures of class I ubiquitin-conjugating enzymes are highly conserved: crystal structure of yeast Ubc4. PUBMED:8268156
Cook WJ, Martin PD, Edwards BF, Yamazaki RK, Chau V; , Biochemistry 1997;36:1621-1627.: Crystal structure of a class I ubiquitin conjugating enzyme (Ubc7) from Saccharomyces cerevisiae at 2.9 angstroms resolution. PUBMED:9048545
Koonin EV, Abagyan RA; , Nat Genet 1997;16:330-331.: TSG101 may be the prototype of a class of dominant negative ubiquitin regulators. PUBMED:9241264
Ponting CP, Cai YD, Bork P , J Mol Med 1997;75:467-469.: The breast cancer gene product TSG101: a regulator of ubiquitination? PUBMED:9253709
Burroughs AM, Jaffee M, Iyer LM, Aravind L;, J Struct Biol. 2008;162:205-218.: Anatomy of the E2 ligase fold: implications for enzymology and evolution of ubiquitin/Ub-like protein conjugation. PUBMED:18276160

InterPro entry IPR000608

The post-translational attachment of ubiquitin () to proteins (ubiquitinylation) alters the function, location or trafficking of a protein, or targets it to the 26S proteasome for degradation PUBMED:15556404, PUBMED:15196553, PUBMED:15454246. Ubiquitinylation is an ATP-dependent process that involves the action of at least three enzymes: a ubiquitin-activating enzyme (E1, ), a ubiquitin-conjugating enzyme (E2), and a ubiquitin ligase (E3, , ), which work sequentially in a cascade PUBMED:14998368. The E1 enzyme mediates an ATP-dependent transfer of a thioester-linked ubiquitin molecule to a cysteine residue on the E2 enzyme. The E2 enzyme () then either transfers the ubiquitin moiety directly to a substrate, or to an E3 ligase, which can also ubiquitinylate a substrate.

There are several different E2 enzymes (over 30 in humans), which are broadly grouped into four classes, all of which have a core catalytic domain (containing the active site cysteine), and some of which have short N- and C-terminal amino acid extensions: class I enzymes consist of just the catalytic core domain (UBC), class II possess a UBC and a C-terminal extension, class III possess a UBC and an N-terminal extension, and class IV possess a UBC and both N- and C-terminal extensions. These extensions appear to be important for some subfamily function, including E2 localisation and protein-protein interactions PUBMED:15545318. In addition, there are proteins with an E2-like fold that are devoid of catalytic activity, but which appear to assist in poly-ubiquitin chain formation.

Clan

This family is a member of clan UBC (CL0208), which contains the following 4 members:

RWD UEV UFC1 UQ_con

Gene Ontology

Molecular function	small conjugating protein ligase activity (GO:0019787)
Biological process	post-translational protein modification (GO:0043687)
Biological process	regulation of protein metabolic process (GO:0051246)

External database links

HOMSTRAD:	uce
PANDIT:	PF00179
PROSITE:	PDOC00163
SCOP:	1aak
SMART:	UBCc
SYSTERS:	UQ_con

Domain organisation

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

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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 (72) Full (4101) NCBI (6222) Metagenomics (318)
Viewer:

Formatting options

Alignment:	Seed (72) Full (4101)
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 (72) Full (4101) NCBI (6222) Metagenomics (318)
Full length sequences	Full-sequences (4101)

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 HMMER2.

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:

Prosite

Previous IDs:

none

Type:

Domain

Author:

Ponting CP, Schultz J, Bork P, Finn RD

Number in seed:

72

Number in full:

4101

Average length of the domain:

134.90 aa

Average identity of full alignment:

28 %

Average coverage of the sequence by the domain:

52.39 %

HMM information

HMM build commands:

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

search method: hmmsearch -Z 9421015 -E 1000 HMM pfamseq

Model details:

Parameter	Sequence	Domain
Gathering cut-off	20.4	20.4
Trusted cut-off	20.4	20.4
Noise cut-off	20.3	20.3

Model length:

140

Family (HMM) version:

19

Download:

download the raw HMM for this family

Species distribution

Tree controls

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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

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Interactions

There are 9 interactions for this family. More...

U-box ubiquitin zf-C3HC4 UBA Cbl_N2 E2_bind ThiF HECT UQ_con

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 MSD 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 UQ_con domain has been found.

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Family: UQ_con (PF00179)

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