Testin

TES
Available structures PDB Ortholog search: PDBe RCSB List of PDB id codes 2IYB, 2XQN
Identifiers
Aliases	TES, TESS, TESS-2, testin LIM domain protein
External IDs	OMIM: 606085; MGI: 105081; HomoloGene: 41051; GeneCards: TES; OMA:TES - orthologs
Gene location (Human) Chr. Chromosome 7 (human)[1] Band 7q31.2 Start 116,210,506 bp[1] End 116,258,783 bp[1]
Gene location (Mouse) Chr. Chromosome 6 (mouse)[2] Band 6 A2|6 7.67 cM Start 17,065,148 bp[2] End 17,105,827 bp[2]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in tail of epididymis seminal vesicula saphenous vein gastric mucosa superficial temporal artery muscle layer of sigmoid colon Descending thoracic aorta nipple myometrium smooth muscle tissue Top expressed in retinal pigment epithelium pyloric antrum left colon spermatid seminiferous tubule genital tubercle granulocyte endothelial cell of lymphatic vessel medullary collecting duct gastric mucosa More reference expression data BioGPS n/a
Gene ontology Molecular function zinc ion binding protein binding metal ion binding RNA binding cadherin binding Cellular component cell junction plasma membrane nucleus focal adhesion cytoplasm cytosol protein-containing complex Biological process regulation of cell population proliferation negative regulation of cell population proliferation Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 26136 21753 Ensembl ENSG00000135269 ENSMUSG00000029552 UniProt Q9UGI8 P47226 RefSeq (mRNA) NM_015641 NM_152829 NM_011570 NM_207176 RefSeq (protein) NP_056456 NP_690042 n/a Location (UCSC) Chr 7: 116.21 – 116.26 Mb Chr 6: 17.07 – 17.11 Mb PubMed search [3] [4]
Wikidata
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Testin (also known as TESS) is a protein that in humans is encoded by the TES gene located on chromosome 7.^[5] TES is a 47 kDa protein composed of 421 amino acids found at focal adhesions and is thought to have a role in regulation of cell motility.^[6] In addition to this, TES functions as a tumour suppressor.^[7] The TES gene is located within a fragile region of chromosome 7, and the promoter elements of the TES gene have been shown to be susceptible to methylation – this prevents the expression of the TES protein. TES came to greater prominence towards the end of 2007 as a potential mechanism for its tumour suppressor function was published.

Tes is composed of the following domains:

The structures of the Cysteine rich domain and the PET domain are not known. LIM domains, however, are known as modulators of protein interactions.^[8] LIM domain consist of 2 zinc fingers separated by 2 hydrophobic amino acids (generally a phenylalanine and then a leucine).

TES does not appear to be an enzyme; rather it is a protein that mediates/regulates cellular functions via protein–protein interactions. Pull down experiments^[9] reveal that TES has putative interactions mediated by the indicated domain:

Garvalov et al. showed that the interaction between TES & zyxin were direct, using recombinant proteins expressed in E. coli.^[9]

Some of the potential binding partners (Zyxin, mENA) can be found in focal adhesion complexes; the range of binding partners indicates a potential role for TES in-between 'privileged' Actin polymerisation and focal adhesion contacts to the extracellular matrix. This tallies with the observation that GFP-tagged TES can be seen at focal adhesions.

In December 2007, Boeda, Briggs et al.^[10] showed that the third LIM domain of TES displaces Mena from its usual subcellular positions (focal adhesions or the cell leading edge). The ENA/VASP protein family (of which Mena is a member) are anchored to specific proteins within the cell by a peptide motif consisting of a phenylalanine residue, followed by four proline residues – known as a FPPPP motif. It is the EVH1 domains of VASP/EVL proteins that directly contact the FPPPP motif. The precise architecture of TES:MENA binding was revealed by X-ray crystallography, and showed that the 3rd LIM domain of TES covered up the FPPPP binding site within Menas EVH1 domain. Isothermal titration calorimetry showed that TES has a greater affinity for Mena than its canonical FPPPP ligand, as presented in the focal adhesion protein zyxin. Using microscopy it was shown that either over-expression of GFP-tagged TES, or just the tagged third LIM domain displaced Mena from focal adhesions and reduced mean cell velocity.

These finding were significant given that Mena is often over-expressed in cancer cells, and is thought to be partly responsible for cancer cell motility, and therefore a factor in cancer metastasis. TES is conversely often not produced in cancer cells. It is possible that a drug designed to mimic TES's interaction with Mena could be used to prevent metastasis and thus development of secondary tumours in cancer patients. The work was widely reported in the British press (the work was carried out by Cancer Research UK),^[11][12][13] and also in the international press.^[14][15]

Based on the observations that:^{[citation needed]}

• Mammalian cell derived TES binding Zyxin
• E. coli-produced recombinant TES (rTES) does not bind Zyxin
• An rTES construct composed of residues 201–421 (i.e., the linker and all 3 LIM domains) does bind Zyxin
• The above rTES construct binds an N-terminal rTES construct, consisting of the cysteine rich and PET domains – IE, the two-halves of TES interact with each other.

Garvalov et al. propose that TES exists in two conformational states: A 'closed' state where the N & C halves of TES interact, obscuring the Zyxin binding site in LIM1, and an 'open' state where the Zyxin binding site is accessible and the two halves no-longer interact in the same fashion, if at all. The regulatory mechanism switching between the two states is not presently fully understood.

In RNAi experiments, cells that had impaired TES expression showed an inability to correctly organise their focal adhesions and actin stress fibres.

In gene knockout experiments, transgenic mice lacking both copies of the TES gene displayed an increased susceptibility to tumour formation when challenged with a carcinogen. Mice retaining the TES gene were less susceptible: thus, TES is a tumour suppressor gene.