Such a function was suggested for 5-methyltetrahydropteroyltriglutamate-homocysteine methyltransferase (Met6) [112] and for Ssa1 and Ssa2 proteins, members of Hsp70 family, which were shown to contribute to the adaptation of to temperature variations [104]. contamination, such as the adhesion to host cells, interactions with plasma homeostatic proteolytic cascades, responses to stress conditions and molecular mimicry. The documented knowledge of the functions of these proteins in pathogenicity has utility for assisting the design of new therapeutic, diagnostic and preventive strategies against candidiasis. yeast, cell wall, protein moonlighting, non-classical secretion, adhesion, plasminogen, match system, contact system, stress protection, molecular mimicry, enolase, glyceraldehyde-3-phosphate dehydrogenase 1. Introduction: Moonlighting ProteinsDefinition and Classification Proteins are multifunctional by nature. The largest of them are divided into unique domains or composed of individual subunits designed to interact with a wide variety of molecular partners. Proteins can perform multiple physiologically relevant functions due to gene fusion, option mRNA splicing, proteolytic generation of different protein variants or promiscuous enzyme activity. However, none of these relatively well-understood molecular mechanisms underly the enigmatic behavior of a group of multitasking proteins termed moonlighting proteins by Jeffery in 1999 [1]. A moonlighting protein is a single polypeptide chain that has a usually evolutionally conserved function but performs an additional unrelated function via a priori unexpected interactions with non-canonical molecular targets. These extra functions often occur at an unauthorized subcellular or extracellular location which seems to be contrary to the classical rules of protein sorting. The presence of two or even more essentially different functions in Eicosapentaenoic Acid a single moonlighting protein can also depend around the concentration of substrates or additional ligands and the oligomerization state or the formation of complexes with other proteins, often occurring without any essential structural alterations of these molecules [1,2]. The first examples of proteins displaying two fundamentally different and apparently unrelated functions were reported by Piatigorsky and coworkers [3,4], who found that individual users of a crystalline family of structural proteins of the eye lens were identical, i.e., share the same gene, with specific cytoplasmic enzymes. However, the term gene sharing proposed by those experts was not broadly accepted because of its ambiguity. The clear-cut definition of moonlighting proteins proposed by Jeffrey [1], although sometimes criticized as too restrictive [5], precisely distinguishes this subset of much broader class of multifunctional proteins. Currently, several hundred confirmed moonlighting proteins are registered in special databases such as MoonProt Database [6] (www.moonlightingproteins.org), MoonDB [7] Eicosapentaenoic Acid and MultitaskDB [8]. The quick increase in the explained cases of this type of multitasking protein in recent Mouse monoclonal to Ki67 years suggests the possibility that many monofunctional proteins will be found in the future to moonlight. Because of the tremendous quantity of combined functions (moonlighting vs. classic) among Eicosapentaenoic Acid moonlighting proteins, additionally multiplied by the variable distribution of these functions between intracellular/extracellular compartments, a detailed classification of all moonlighting proteins will be problematic. Hence, it has been recently proposed [9] to classify them into two large groups only, thus leaving aside many individual moonlighting proteins with unique features. These two major subsets include (i) trigger enzymes and (ii) intracellular/secreted moonlighting proteins. The first subset represents enzymes that also regulate transcription or translation by direct binding to DNA or RNA, or by binding to other proteinaceous translation or transcription factors [10]. The second group, the largest within the entire class of known moonlighting proteins, includes intracellular proteins: housekeeping enzymes, chaperones, translation factors, DNA-binding proteins and many others that are secreted and either reside attached to the cell surface, acting as receptors for soluble proteins or small molecules, or function in the fluid phase, often for intracellular signaling [9]. The intracellular/secreted moonlighting proteins have been found in organisms from all kingdoms and this type of protein moonlighting has been most widely observed and best characterized in pathogenic bacteria.