Powering down the Pfam website
On October 5th, we will start redirecting the traffic from Pfam (pfam.xfam.org) to InterPro (www.ebi.ac.uk/interpro). The Pfam website will be available at pfam-legacy.xfam.org until January 2023, when it will be decommissioned. You can read more about the sunset period in our blog post.

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.
164  structures 1033  species 0  interactions 4426  sequences 29  architectures

Family: POLO_box (PF00659)

Summary: POLO box duplicated region

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.

POLO box duplicated region Provide feedback

No Pfam abstract.

Literature references

  1. Leung GC, Hudson JW, Kozarova A, Davidson A, Dennis JW, Sicheri F; , Nat Struct Biol. 2002;9:719-724.: The Sak polo-box comprises a structural domain sufficient for mitotic subcellular localization. PUBMED:12352953 EPMC:12352953

External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR000959

A subgroup of serine/threonine protein kinases, Polo or Polo-like kinases play multiple roles during the cell cycle. Polo kinases are required at several key points through mitosis, starting from control of the G2/M transition through phosphorylation of Cdc25C and mitotic cyclins. They are also involved in meiosis I as regulators of kinetochore function [ PUBMED:22018922 , PUBMED:25533956 ]. Polo kinases are characterised by an amino terminal catalytic domain, and a carboxy terminal non-catalytic domain consisting of three blocks of conserved sequences known as polo boxes which form one single functional domain [ PUBMED:9914175 ]. The domain is named after its founding member encoded by the polo gene of Drosophila melanogaster [ PUBMED:1660828 ]. This domain of around 70 amino acids has been found in species ranging from yeast to mammals. Polo boxes appear to mediate interaction with multiple proteins through protein:protein interactions; some but not all of these proteins are substrates for the kinase domain of the molecule [ PUBMED:12615979 ].

The crystal structure of the polo domain of the murine protein, Sak, is dimeric, consisting of two alpha-helices and two six-stranded beta-sheets [ PUBMED:12352953 ]. The topology of one polypeptide subunit of the dimer consists of, from its N- to C terminus, an extended strand segment, five beta-strands, one alpha-helix (A) and C-terminal beta-strand. Beta-strands from one subunit form a contiguous antiparallel beta-sheet with beta-strands from the second subunit. The two beta-sheets pack with crossing angle of 110 degrees, orienting the hydrophobic surfaces inward and the hydrophilic surfaces outward. Helix A, which is colinear with beta-strand 6 of the same polypeptide, buries a large portion of the non-overlapping hydrophobic beta-sheet surfaces. Interactions involving helices A comprise a majority of the hydrophobic core structure and also the dimer interface.

Point mutations in the Polo box of the budding yeast Cdc5 protein abolish the ability of overexpressed Cdc5 to interact with the spindle poles and to organise cytokinetic structures [ PUBMED:10594031 ].

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 Polo-box (CL0708), which has the following description:

This superfamily includes Polo domains which consist of an anti-parallel 6-stranded beta-sheet that lies across a C-terminal alpha-helix. These domains are ussually present in two copies and forms dimers that mediate protein-protein interactions [1,2,3]. Polo boxes are present in polo-like kinases involved in the control of cell cycle progression.

The clan contains the following 5 members:

Plk4_PB1 Plk4_PB2 POLO_box Polo_box_2 Polo_box_3


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: Prosite
Previous IDs: none
Type: Family
Sequence Ontology: SO:0100021
Author: Bateman A , Mistry J , Sammut SJ
Number in seed: 198
Number in full: 4426
Average length of the domain: 62.8 aa
Average identity of full alignment: 27 %
Average coverage of the sequence by the domain: 17.19 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 61295632 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 23.0 23.0
Trusted cut-off 23.0 23.0
Noise cut-off 22.9 22.9
Model length: 61
Family (HMM) version: 21
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


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.


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 POLO_box domain has been found. There are 164 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 sequence.

Loading structure mapping...

AlphaFold Structure Predictions

The list of proteins below match this family and have AlphaFold predicted structures. Click on the protein accession to view the predicted structure.

Protein Predicted structure External Information
A0A044U7C5 View 3D Structure Click here
A0A0K0DYW6 View 3D Structure Click here
A0A0K0E724 View 3D Structure Click here
A0A0K0EF17 View 3D Structure Click here
A0A0K0JQP5 View 3D Structure Click here
A0A0N4UIV5 View 3D Structure Click here
A0A3P7FBZ3 View 3D Structure Click here
A4HXE5 View 3D Structure Click here
A8WHV5 View 3D Structure Click here
B0S6K2 View 3D Structure Click here
D3ZY07 View 3D Structure Click here
E7EXD4 View 3D Structure Click here
P0C8M8 View 3D Structure Click here
P32562 View 3D Structure Click here
P34331 View 3D Structure Click here
P50528 View 3D Structure Click here
P52304 View 3D Structure Click here
P53350 View 3D Structure Click here
P53351 View 3D Structure Click here
P62205 View 3D Structure Click here
Q07832 View 3D Structure Click here
Q20845 View 3D Structure Click here
Q2TA25 View 3D Structure Click here
Q4D1J3 View 3D Structure Click here
Q4DPI3 View 3D Structure Click here
Q4FZD7 View 3D Structure Click here
Q57VI0 View 3D Structure Click here
Q5ABG0 View 3D Structure Click here
Q5R4L1 View 3D Structure Click here
Q5UES2 View 3D Structure Click here
Q60806 View 3D Structure Click here
Q62673 View 3D Structure Click here
Q6DRK7 View 3D Structure Click here
Q86HN7 View 3D Structure Click here
Q8SWM6 View 3D Structure Click here
Q9H4B4 View 3D Structure Click here
Q9N2L7 View 3D Structure Click here
Q9NYY3 View 3D Structure Click here
Q9R011 View 3D Structure Click here
Q9R012 View 3D Structure Click here