UniProt release 15.9

Trichophyton tonsurans: an uninvited guest at the World Judo Championships

The World Judo Championships 2009 took place few weeks ago in Rotterdam, Netherlands. A sword of Damocles was hanging over this competition. Its name: Trichophyton tonsurans, a fungal parasite. Japanese academics have raised the alarm: the national sports of sumo and judo may decline because of the rapid spread of this skin-eating fungus. The infection is similar to athlete's foot. It is highly infectious and difficult to treat. It causes itchy red patches on the neck, face and upper body. It often affects the scalp and eventually attacks hair follicles, causing baldness. This distribution is consistent with areas of contact during the grappling that is at the heart of sumo and judo sports, suggesting that the fungus spreads by direct skin-to-skin contact.

Trichophyton tonsurans is just one member of a large family of fungal parasites, called dermatophytes. Dermatophytes are not opportunists, but true pathogens that infect nonliving, cornified layers of the skin, hair and nail in warm and moist environments suitable for proliferation. They are the most common agents of superficial mycoses.

The virulence of dermatophytes is largely due to the secretion of many different proteolytic enzymes. Their genomes encode dozens of secreted proteases. To improve the digestion efficiency of infected tissues, the pathogens secrete proteolytic "cocktails" composed of endo- and exoproteases.

During keratin degradation and digestion, dermatophytes also excrete sulphite through an efflux pump (SSU1). Sulphite reduces cystines, which are abundant in keratins, into cysteine and S-sulphocysteine. As a result, the proteins become more prone to hydrolysis by the secreted "protease cocktail". SSU1 may also play an additional role. Indeed, living in a cyst(e)ine-rich environment, such as the epidermal stratum corneum, hair and nails, may have the fatal drawback of sulphur toxicity. Thus, by excreting excess sulphur as sulphate and sulphite, the pump may also protect dermatophytes from poisoning.

Two large families of secreted endoproteases have been identified in dermatophytes: the subtilisin-like endoproteases SUB1 through SUB7 and the metalloproteinases, also called fungalysins. The exoproteases comprise dipeptidylpeptidases, such as DPP4 and DPP5, aminopeptidases, such as LAP1 and LAP2, as well as carboxypeptidases, such as MCPA, MCPB, SCPA and SCPB. All these proteins have been manually annotated and integrated into UniProtKB/Swiss-Prot.

Orthologous proteins have also been identified in Trichophyton rubrum, the predominant causative agent for superficial dermatomycosis, Arthroderma benhamiae, another dermatophyte triggering severe inflammatory responses in humans, Trichophyton equinum causing ringworm in horses, Nannizzia otae, also known as Microsporum canis, a common zoophilic fungal parasite, and several other less studied dermatophyte species.

In addition to virulence factors, the complete proteome of Nannizzia otae is now available in UniProtKB.

Dermatophytes are fascinating examples of evolutionary adaptation. These fungi have developed sophisticated weapons at our expense to achieve their goal: survival. Like David against Goliath, they have a good probability of winning the battle and sumo wrestlers may well lose their top-knots.

As of this release, 110 dermatophyte virulence factors have been manually annotated and integrated into UniProtKB/Swiss-Prot.

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Cross-references to Genevestigator

Cross-references have been added to Genevestigator, a reference expression database and meta-analysis system. It allows biologists to study the expression and regulation of genes in a broad variety of contexts by summarizing information from hundreds of microarray experiments into easily interpretable results.

Genevestigator is available at https://www.genevestigator.com/.

The format of the explicit links in the flat file is:

P04637:
DR   Genevestigator; P04637; -.

Changes concerning keywords

New keyword:

• Fimbrium biogenesis

Changes in subcellular location controlled vocabulary

Modified subcellular locations:

• Glycosome lumen -> Glycosome matrix
• Glyoxysome lumen -> Glyoxysome matrix

Deleted subcellular locations:

• Host lipid droplet membrane
• Lipid droplet membrane

Changes concerning the controlled vocabulary for PTMs

New terms for the feature key 'Cross-link' ('CROSSLNK' in the flat file):

• S-Lysyl-methionine sulfilimine (Met-Lys) (interchain with K-...)
• S-Lysyl-methionine sulfilimine (Lys-Met) (interchain with M-...)