Salivary MUC7 Antimicrobial Peptide:RIM101 Response and Mechanism of Action.

产品描述（申请人提供）：阳离子抗菌肽（CAMP）是一种12-50个残基长的肽，具有高含量的阳离子氨基酸，其特征是对包括病原菌、真菌和寄生虫在内的广泛微生物具有强活性。尽管进行了深入的研究，积累了大量详细的资料，但人们对它们的作用方式并不十分了解。该提案是正在进行的关于MUC 7 12-mer的性质和作用机制的阐明的研究的一部分，MUC 7 12-mer是一种来自低分子量唾液粘蛋白7的抗菌肽。该肽对机会性真菌病原体白色念珠菌和致龋口腔细菌变形链球菌具有有效的抗微生物特性。我们最近采用了一种全球性的方法，能够同时研究抗菌肽作用的许多不同方面。在这种方法中，同时测试了对数千个酵母酿酒酵母缺失突变体的肽的改变的亲和性。在已确定的缺失赋予超敏反应的肽，许多涉及的基因与RIM 101信号通路，最有名的响应环境pH值的变化。在第一个具体的目的，我们将确认该途径的诱导MUC 7肽和研究其作用的肽与靶细胞的相互作用。在第二个目标中，我们将测试一个假设，该假设提出MUC 7肽存在两种不同的作用机制，一种是杀真菌的，另一种是抗真菌的，并将研究RIM 101信号传导如何与两者相关。我们也将这项研究扩大到致病酵母C。白念珠菌和钙信号，我们最近发现它在防御MUC 7肽中起作用，类似于S.啤酒。在第三个目标中，我们将通过直接选择S来扩展原始的适应度分析。酿酒酵母缺失突变体对肽具有抗性。 公共卫生相关性：由于新抗生素和抗真菌剂的发现率下降以及病原体的耐药菌株的传播，迫切需要开发新类别的抗微生物疗法。抗菌肽是一种潜在的新药来源。最近完成的酵母MUC 7肽缺失筛选的结果为研究其作用机制提供了新的方向。

DESCRIPTION (provided by applicant): Cationic antimicrobial peptides (CAMP), 12-50 residues long eptides with high content of cationic amino acids, are characterized by strong activities directed against broad range of microorganisms including pathogenic bacteria, fungi and parasites. Despite intensive research and wealth of accumulated detailed information, their modes of action are not well understood. This proposal is a part of the ongoing research on elucidation of properties and mechanisms of action of MUC7 12-mer, an antimicrobial peptide derived from the low molecular-weight salivary mucin 7. This peptide has potent antimicrobial properties against opportunistic fungal pathogen Candida albicans and cariogenic oral bacterium Streptococcus mutans. We have recently employed a global approach enabling study of many different aspects of action of antimicrobial peptides at once. In this approach altered susceptibilities to the peptide of thousands deletion mutants of yeast Saccharomyces cerevisiae were tested simultaneously. Among identified deletions conferring hypersensitivity to the peptide, many involved genes associated with the RIM101 signaling pathway, best known as a response to changes in environmental pH. In the first Specific Aim we will confirm induction of this pathway by the MUC7 peptide and investigate its role in interaction of the peptide with target cells. In the second Aim we will test a hypothesis proposing existence of two distinct mechanisms of action of the MUC7 peptide, one fungicidal and the other fungiststic, and will investigate how the RIM101 signaling relates to both. We will also expand this study to the pathogenic yeast C. albicans and calcium signaling, which we have recently identified as playing a role in defense against the MUC7 peptide, analogous to that of the RIM101 response in S. cerevisiae. In the third Aim we will extend the original fitness profiling by direct selection for S. cerevisiae deletion mutants resistant to the peptide. Public Health Relevance: Due to the declining rate of discovery of new antibiotics and antifungal agents, and spread of resistant strains of pathogens, there is urgent need for development of new classes of antimicrobial therapies. Antimicrobial peptides are a potential source of novel drugs. Results of recently completed yeast deletion screen with MUC7 peptide provide new directions for studying its mechanisms of action.