Summary

Protein prenyltransferase alpha subunit repeat

Both farnesyltransferase (FT) and geranylgeranyltransferase 1 (GGT1) recognise a CaaX motif on their substrates where 'a' stands for preferably aliphatic residues, whereas GGT2 recognises a completely different motif. Important substrates for FT include, amongst others, many members of the Ras superfamily. GGT1 substrates include some of the other small GTPases and GGT2 substrates include the Rab family [2].

Literature references

Strickland CL, Windsor WT, Syto R, Wang L, Bond R, Wu Z, Schwartz J, Le HV, Beese LS, Weber PC; , Biochemistry 1998;37:16601-16611.: Crystal structure of farnesyl protein transferase complexed with a CaaX peptide and farnesyl diphosphate analogue. PUBMED:9843427
Maurer-Stroh S, Washietl S, Eisenhaber F; , Genome Biol 2003;4:212.: Protein prenyltransferases. PUBMED:12702202

InterPro entry IPR002088

Protein prenylation is the posttranslational attachment of either a farnesyl group or a geranylgeranyl group via a thioether linkage (-C-S-C-) to a cysteine at or near the carboxyl terminus of the protein. Farnesyl and geranylgeranyl groups are polyisoprenes, unsaturated hydrocarbons with a multiple of five carbons; the chain is 15 carbons long in the farnesyl moiety and 20 carbons long in the geranylgeranyl moiety. There are three different protein prenyltransferases in humans: farnesyltransferase (FT) and geranylgeranyltransferase 1 (GGT1) share the same motif (the CaaX box) around the cysteine in their substrates, and are thus called CaaX prenyltransferases, whereas geranylgeranyltransferase 2 (GGT2, also called Rab geranylgeranyltransferase) recognises a different motif and is thus called a non-CaaX prenyltransferase. Protein prenyltransferases are currently known only in eukaryotes, but they are widespread, being found in vertebrates, insects, nematodes, plants, fungi and protozoa, including several parasites.

Each protein consists of two subunits, alpha and beta; the alpha subunit of FT and GGT1 is encoded by the same gene, FNTA. The alpha subunit is thought to participate in a stable complex with the isoprenyl substrate; the beta subunit binds the peptide substrate. In the alpha subunits of both types of protein prenyltransferases, seven tetratricopeptide repeats are formed by pairs of helices that are stabilised by conserved intercalating residues. The alpha subunits of GGT2 in mammals and plants also have an immunoglobulin-like domain between the fifth and sixth tetratricopeptide repeat, as well as leucine-rich repeats at the carboxyl terminus. The functions of these additional domains in GGT2 are as yet undefined, but they are apparently not directly involved in the interaction with substrates and Rab escort proteins. The tetratricopeptide repeats of the alpha subunit form a right-handed superhelix, which embraces the (alpha-alpha)6 barrel of the beta subunit PUBMED:1622936.

Gene Ontology

Molecular function	protein prenyltransferase activity (GO:0008318)
Biological process	protein amino acid prenylation (GO:0018346)

External database links

HOMSTRAD:	PPTA
PANDIT:	PF01239
PROSITE:	PDOC00703
SCOP:	1ft1
SYSTERS:	PPTA

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 (143) Full (1264) NCBI (1769) Metagenomics (11)
Viewer:

Formatting options

Alignment:	Seed (143) Full (1264)
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 (143) Full (1264) NCBI (1769) Metagenomics (11)
Full length sequences	Full-sequences (1264)

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:

Repeat

Author:

Finn RD, Bateman A

Number in seed:

143

Number in full:

1264

Average length of the domain:

30.30 aa

Average identity of full alignment:

27 %

Average coverage of the sequence by the domain:

7.63 %

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	20.2	20.2
Trusted cut-off	20.2	20.2
Noise cut-off	20.1	20.1

Model length:

31

Family (HMM) version:

15

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 4 interactions for this family. More...

PPTA Prenyltrans GDI RabGGT_insert

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 PPTA domain has been found.

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Family: PPTA (PF01239)

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