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 1056  species 0  interactions 1412  sequences 27  architectures

Family: Scs3p (PF10261)

Summary: Inositol phospholipid synthesis and fat-storage-inducing TM

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.

Inositol phospholipid synthesis and fat-storage-inducing TM Provide feedback

This is a family of transmembrane proteins which are variously annotated as possibly being inositol phospholipid synthesis protein [1] and fat-storage-inducing. The members are conserved from yeasts to humans and are localised to the endoplasmic reticulum where they are involved in triglyceride lipid droplet formation [2].

Literature references

  1. Hosaka K, Nikawa J, Kodaki T, Ishizu H, Yamashita S;, J Biochem. 1994;116:1317-1321.: Cloning and sequence of the SCS3 gene which is required for inositol prototrophy in Saccharomyces cerevisiae. PUBMED:7706223 EPMC:7706223

  2. Gross DA, Snapp EL, Silver DL;, PLoS One. 2010;5:e10796.: Structural insights into triglyceride storage mediated by fat storage-inducing transmembrane (FIT) protein 2. PUBMED:20520733 EPMC:20520733

Internal database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR019388

This entry represents the fat storage-inducing transmembrane (FIT) family of proteins, which play an important role in lipid droplet accumulation. They are endoplasmic reticulum resident membrane proteins that induce lipid droplet accumulation in cell culture and when expressed in mouse liver [ PUBMED:18160536 ]; they mediate the partitioning of triglyceride from the ER into cytosolic fatty droplets by an as-yet undetermined mechanism. The ability to store fat in the form of cytoplasmic triglyceride droplets is conserved from Saccharomyces cerevisiae to humans [ PUBMED:18160536 ]. The FIT family of proteins are not involved in triglyceride biosynthesis [ PUBMED:20520733 ].

FIT1 and FIT2 proteins are six-transmembrane-domain containing proteins with both the N and C termini residing in the cytosol. FIT2 is the more anciently conserved homologue of the FIT family; this family of proteins do not share sequence similarity to known proteins or domains.

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...

Loading domain graphics...

Pfam Clan

This family is a member of clan pap2 (CL0525), which has the following description:

The PAP2 superfamily is characterised by being mult-helical, with the core consisting of a 5-helical bundle. Normally the family will bind cofactor at the beginning of the third helix. The superfamily includes the enzyme type 2 phosphatidic acid phosphatase (PAP2), Glucose-6-phosphatase EC:, Phosphatidylglycerophosphatase B EC: and bacterial acid phosphatase EC: The family also includes a variety of haloperoxidases [1,2] that function by oxidising halides in the presence of hydrogen peroxide to form the corresponding hypohalous acids.

The clan contains the following 5 members:

DUF212 PAP2 PAP2_3 PAP2_C Scs3p


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 (reference proteomes) using the family HMM. We also generate alignments using four representative proteomes (RP) sets and the UniProtKB 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.

Representative proteomes UniProt
Jalview View  View  View  View  View  View  View 
HTML View  View           
PP/heatmap 1 View           

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

Key: ✓ available, x not generated, not available.

Format an alignment

Representative proteomes UniProt

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.

Representative proteomes UniProt
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.

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...


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: KOGs (KOG3750)
Previous IDs: none
Type: Family
Sequence Ontology: SO:0100021
Author: KOGs, Finn RD , Coggill P
Number in seed: 74
Number in full: 1412
Average length of the domain: 178.00 aa
Average identity of full alignment: 26 %
Average coverage of the sequence by the domain: 62.83 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 57096847 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 30.5 30.5
Trusted cut-off 30.5 30.5
Noise cut-off 30.1 30.4
Model length: 246
Family (HMM) version: 11
Download: download the raw HMM for this family

Species distribution

Sunburst controls


Weight segments by...

Change the size of the sunburst


Colour assignments

Archea Archea Eukaryota Eukaryota
Bacteria Bacteria Other sequences Other sequences
Viruses Viruses Unclassified Unclassified
Viroids Viroids Unclassified sequence Unclassified sequence


Align selected sequences to HMM

Generate a FASTA-format file

Clear selection

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


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


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.

trRosetta Structure

The structural model below was generated by the Baker group with the trRosetta software using the Pfam UniProt multiple sequence alignment.

The InterPro website shows the contact map for the Pfam SEED alignment. Hovering or clicking on a contact position will highlight its connection to other residues in the alignment, as well as on the 3D structure.

Improved protein structure prediction using predicted inter-residue orientations. Jianyi Yang, Ivan Anishchenko, Hahnbeom Park, Zhenling Peng, Sergey Ovchinnikov, David Baker Proceedings of the National Academy of Sciences Jan 2020, 117 (3) 1496-1503; DOI: 10.1073/pnas.1914677117;