title: In Vitro Identification of Histatin 5 Salivary Complexes.
abstract: With recent progress in the analysis of the salivary proteome, the number of salivary proteins identified has increased dramatically. However, the physiological functions of many of the newly discovered proteins remain unclear. Closely related to the study of a protein's function is the identification of its interaction partners. Although in saliva some proteins may act primarily as single monomeric units, a significant percentage of all salivary proteins, if not the majority, appear to act in complexes with partners to execute their diverse functions. Coimmunoprecipitation (Co-IP) and pull-down assays were used to identify the heterotypic complexes between histatin 5, a potent natural antifungal protein, and other salivary proteins in saliva. Classical protein-protein interaction methods in combination with high-throughput mass spectrometric techniques were carried out. Co-IP using protein G magnetic Sepharose TM beads suspension was able to capture salivary complexes formed between histatin 5 and its salivary protein partners. Pull-down assay was used to confirm histatin 5 protein partners. A total of 52 different proteins were identified to interact with histatin 5. The present study used proteomic approaches in conjunction with classical biochemical methods to investigate protein-protein interaction in human saliva. Our study demonstrated that when histatin 5 is complexed with salivary amylase, one of the 52 proteins identified as a histatin 5 partner, the antifungal activity of histatin 5 is reduced. We expected that our proteomic approach could serve as a basis for future studies on the mechanism and structural-characterization of those salivary protein interactions to understand their clinical significance.
authors.affiliation: The University of Western Ontario, Schulich School of Medicine & Dentistry, Department of Dentistry and Biochemistry, London, ON, Canada.|UNESP - Univ. Estadual Paulista - Araraquara Dental School, Department of Dental Materials and Prosthodontics, São Paulo, Brazil.|CEUMA University, Department of Prosthodontics, Sao Luis, MA, Brazil.|Department of Pediatric Dentistry, Orthodontics and Public Health, Bauru Dental School, USP - University of São Paulo, Bauru, SP, Brazil.
authors.forename: Eduardo B
authors.initials: EB
authors.lastname: Moffa
authors.affiliation: Department of Pediatric Dentistry, Orthodontics and Public Health, Bauru Dental School, USP - University of São Paulo, Bauru, SP, Brazil.
authors.forename: Maria A A M
authors.initials: MA
authors.lastname: Machado
authors.affiliation: The University of Western Ontario, Schulich School of Medicine & Dentistry, Department of Dentistry and Biochemistry, London, ON, Canada.|University of São Paulo, School of Dentistry, São Paulo, SP, Brazil.
authors.forename: Maria C M
authors.initials: MC
authors.lastname: Mussi
authors.affiliation: The University of Western Ontario, Schulich School of Medicine & Dentistry, Department of Dentistry and Biochemistry, London, ON, Canada.
authors.forename: Yizhi
authors.initials: Y
authors.lastname: Xiao
authors.affiliation: UNESP - Univ. Estadual Paulista - Institute of Chemistry - Department of Biochemistry and Technological Chemistry, São Paulo, Brazil.
authors.forename: Saulo S
authors.initials: SS
authors.lastname: Garrido
authors.affiliation: UNESP - Univ. Estadual Paulista - Araraquara Dental School, Department of Dental Materials and Prosthodontics, São Paulo, Brazil.
authors.forename: Eunice T
authors.initials: ET
authors.lastname: Giampaolo
authors.affiliation: The University of Western Ontario, Schulich School of Medicine & Dentistry, Department of Dentistry and Biochemistry, London, ON, Canada.
authors.forename: Walter L
authors.initials: WL
authors.lastname: Siqueira
mesh_terms: D000328:Adult; D000681:Amylases / Q000378:metabolism; D005260:Female; D054808:Histatins / Q000378:metabolism*; D006801:Humans; D008297:Male; D013058:Mass Spectrometry; D025941:Protein Interaction Mapping; D012463:Saliva / Q000378:metabolism*; D055815:Young Adult
chemical_list: C068075:HTN3 protein, human; D054808:Histatins; D000681:Amylases