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7  structures 134  species 1  interaction 692  sequences 19  architectures

Family: IP_trans (PF02121)

Summary: Phosphatidylinositol transfer protein

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This is the Wikipedia entry entitled "Phosphatidylinositol transfer protein". More...

Phosphatidylinositol transfer protein Edit Wikipedia article

2a1l.gif
Phosphatidylinositol transfer protein, beta isoform
Identifiers
Symbol IP_trans
Pfam PF02121
InterPro IPR001666
SCOP 1fvz
SUPERFAMILY 1fvz
OPM superfamily 147
OPM protein 2a1l

Phosphatidylinositol transfer protein (PITP) or priming in exocytosis protein 3 (PEP3) is a ubiquitous cytosolic domain involved in transport of phospholipids from their site of synthesis in the endoplasmic reticulum and Golgi to other cell membranes.[1][2]

Biological function[edit]

PITP has been also shown to be an essential component of the polyphosphoinositide synthesis machinery and is hence required for proper signalling by epidermal growth factor and f-Met-Leu-Phe, as well as for exocytosis. The role of PITP in polyphosphoinositide synthesis may also explain its involvement in intracellular vesicular traffic.[1]

Structure and evolution[edit]

Along with the structurally unrelated Sec14p family (found in Pfam PF00650), this family can bind/exchange one molecule of phosphatidylinositol (PI) or phosphatidylcholine (PC) and thus aids their transfer between different membrane compartments. There are three sub-families - all share an N-terminal PITP-like domain, whose sequence is highly conserved. It is described as consisting of three regions. The N-terminal region is thought to bind the lipid and contains two helices and an eight-stranded, mostly antiparallel beta-sheet. An intervening loop region, which is thought to play a role in protein-protein interactions, separates this from the C-terminal region, which exhibits the greatest sequence variation and may be involved in membrane binding. This motif marks PITP as part of the larger SRPBCC (START/RHOalphaC/PITP/Bet v1/CoxG/CalC) domain superfamily.[citation needed]

PITP alpha (UniProt Q00169) has a 16-fold greater affinity for PI than PC. Together with PITP beta (UniProt P48739), it is expressed ubiquitously in all tissues.[3]

Human proteins[edit]

The family of human phosphatidylinositol transfer proteins has several members:

References[edit]

  1. ^ a b Liscovitch M, Cantley LC (1995). "Signal transduction and membrane traffic: the PITP/phosphoinositide connection". Cell 81 (5): 659–662. doi:10.1016/0092-8674(95)90525-1. PMID 7774006. 
  2. ^ Hay JC, Martin TF (December 1993). "Phosphatidylinositol transfer protein required for ATP-dependent priming of Ca(2+)-activated secretion". Nature 366 (6455): 572–5. doi:10.1038/366572a0. PMID 8255295. 
  3. ^ Hsuan J, Cockcroft S (2001). "The PITP family of phosphatidylinositol transfer proteins". Genome Biol. 2 (9): REVIEWS3011. doi:10.1186/gb-2001-2-9-reviews3011. PMC 138965. PMID 11574064. 

This article incorporates text from the public domain Pfam and InterPro IPR001666

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.

Phosphatidylinositol transfer protein Provide feedback

Along with the structurally unrelated Sec14p family (found in PF00650), this family can bind/exchange one molecule of phosphatidylinositol (PI) or phosphatidylcholine (PC) and thus aids their transfer between different membrane compartments. There are three sub-families - all share an N-terminal PITP-like domain, whose sequence is highly conserved. It is described as consisting of three regions. The N-terminal region is thought to bind the lipid and contains two helices and an eight-stranded, mostly antiparallel beta-sheet. An intervening loop region, which is thought to play a role in protein-protein interactions, separates this from the C-terminal region, which exhibits the greatest sequence variation and may be involved in membrane binding. PITP alpha (Q00169) has a 16-fold greater affinity for PI than PC. Together with PITP beta (P48739), it is expressed ubiquitously in all tissues [1].

Literature references

  1. Hsuan J, Cockcroft S; , Genome Biol 2001;2:REVIEWS3011.: The PITP family of phosphatidylinositol transfer proteins. PUBMED:11574064 EPMC:11574064


External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR001666

Phosphatidylinositol transfer protein (PITP) is a ubiquitous cytosolic protein, thought to be involved in transport of phospholipids from their site of synthesis in the endoplasmic reticulum and Golgi to other cell membranes [PUBMED:7774006]. More recently, PITP has been shown to be an essential component of the polyphosphoinositide synthesis machinery and is hence required for proper signalling by epidermal growth factor and f-Met-Leu-Phe, as well as for exocytosis. The role of PITP in polyphosphoinositide synthesis may also explain its involvement in intracellular vesicular traffic [PUBMED:7774006].

Gene Ontology

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

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 Bet_V_1_like (CL0209), which has the following description:

The Bet_V_I family is composed of sequences related to the major Birch (Betula verrucose) pollen antigen Betv1. This allergen is known to cause hayfever, dermatitis, asthma and occasionally anaphylactic shock. The other families in this clan share the same structure as Betv1 which is composed of antiparallel beta sheets and alpha helices. There is a cavity between the beta sheet and a long C terminal helix. The cavity appears to play roles in the binding of lipid molecules [1][2][3] which seems a common feature of the families in this clan.

The clan contains the following 14 members:

AHSA1 Aromatic_hydrox Bet_v_1 COXG DUF1857 DUF2505 DUF3074 DUF3211 DUF3284 IP_trans Polyketide_cyc Polyketide_cyc2 Ring_hydroxyl_A START

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...

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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.

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(4)
Full
(692)
Representative proteomes NCBI
(566)
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(135)
RP35
(169)
RP55
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RP75
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Format an alignment

  Seed
(4)
Full
(692)
Representative proteomes NCBI
(566)
Meta
(0)
RP15
(135)
RP35
(169)
RP55
(310)
RP75
(422)
Alignment:
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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
(4)
Full
(692)
Representative proteomes NCBI
(566)
Meta
(0)
RP15
(135)
RP35
(169)
RP55
(310)
RP75
(422)
Raw Stockholm Download   Download   Download   Download   Download   Download   Download    
Gzipped 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.

Pfam alignments:

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: IPR001666
Previous IDs: none
Type: Family
Author: Mian N, Bateman A
Number in seed: 4
Number in full: 692
Average length of the domain: 221.10 aa
Average identity of full alignment: 45 %
Average coverage of the sequence by the domain: 46.39 %

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 21.3 21.3
Trusted cut-off 21.6 22.4
Noise cut-off 18.6 19.2
Model length: 254
Family (HMM) version: 13
Download: download the raw HMM for this family

Species distribution

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Interactions

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

IP_trans

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 IP_trans domain has been found. There are 7 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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