MOLECULAR BIOLOGY OF PNEUMOCYSTIS CARINII ANTIGENS

描述（改编自申请人摘要）：由 机会性真菌卡氏肺孢子虫是发病的主要原因， 免疫功能低下的宿主，包括艾滋病患者的死亡率。的 该提案的长期目标是描述结构和功能 卡氏肺孢子虫生物学中重要的蛋白质和卡氏肺孢子虫的发病机制 卡氏肺孢子虫肺炎（PCP），以确定潜在的治疗靶点 抵抗感染我们将重点研究一种新发现的小鼠丝氨酸蛋白酶 卡氏肺孢子虫，KEX 1。小鼠卡氏肺孢子虫KEX 1与卡氏肺孢子虫Kexin家族的同源性 真菌蛋白酶和哺乳动物激素原转化酶（弗林蛋白酶）表明， 可能参与其他P. 卡氏原核菌蛋白质，从而在卡氏原核菌生物学中发挥重要作用。 carinii。KEX 1的潜在底物是P的粘附表面抗原。 卡氏梭菌，糖蛋白A（gpA），其必须经过后处理， 在放置到生物体上之前去除保守的前导序列（UCS） 面一种由Kexin家族识别的赖氨酸-精氨酸二肽序列， 在动物和人卡氏肺孢子虫的UCS-gpA连接处发现了这种蛋白酶。 研究人员将测试小鼠卡氏肺孢子虫KEX 1可以 切割小鼠卡氏肺孢子虫UCS-gpA连接。他们还将描述 进一步研究了KEX 1的分子生物学和底物特异性。具体 目的：（1）检测KEX 1的RNA和蛋白水平 在小鼠卡氏肺孢子虫不同生活史形式中的表达;（2）确定 KEX 1蛋白在卡氏肺孢子虫中的亚细胞定位 研究小鼠卡氏肺孢子虫KEX 1的功能方面;和（4）为了 表征小鼠卡氏肺孢子虫KEX1基因的基因组结构。的 对小鼠卡氏肺孢子虫KEX 1的拟议研究将提供比较的基础 卡氏肺孢子虫家族其他成员的类似酶。所有P。 卡氏梭菌合成必须进行后处理的蛋白质种类， 了解kexin样蛋白酶的结构和功能， 卡氏肺孢子虫可能导致设计特异性酶抑制剂， 对这种重要病原体的生物过程产生不利影响。

DESCRIPTION (Adapted from applicant's abstract): Pneumonia caused by the opportunistic fungus Pneumocystis carinii is a major cause of morbidity and mortality in the immunocompromised host, including those with AIDS. The long-range goal of this proposal is to characterize the structure and function of proteins of importance in the biology of P. carinii and the pathogenesis of P. carinii Pneumonia (PCP), in order to identify potential targets for therapy against infection. We will focus on a newly described serine protease of mouse P. carinii, KEX1. The homology of mouse P. carinii KEX1 to the kexin family of fungal proteases and the mammalian prohormone convertases (furins) suggests it may be involved in the proteolytic processing and maturation of other P. carinii proteins, thereby playing an important role in the biology of P. carinii. A potential substrate for KEX1 is the adhesive surface antigen of P. carinii, glycoprotein A (gpA), which must be post-translationally processed to remove a conserved leader sequence (UCS) prior to placement on the organism's surface. A lysine-arginine dipeptide sequence recognized by the kexin family of proteases is found at the UCS-gpA junction in both animal and human P. carinii. The investigators will test the hypothesis that mouse P. carinii KEX1 can cleave the mouse P. carinii UCS-gpA junction. They will also characterize further the molecular biology and substrate specificity of KEX1. The specific aims of the proposal are: (1) To determine the level of KEX1 RNA and protein expression in different life cycle forms of mouse P. carinii; (2) To determine the subcellular location of KEX1 protein in mouse P. carinii; (3) To investigate functional aspects of mouse P. carinii KEX1; and (4) To characterize the genomic organization of the mouse P. carinii KEX1 gene. The proposed studies of mouse P. carinii KEX1 will provide a basis for comparison to similar enzymes in other members of the P. carinii family. Since all P. carinii synthesize protein species that must be post-translationally processed, an understanding of the structure and function of the kexin-like proteases of P. carinii may lead to the design of specific enzyme inhibitors that would adversely affect the biological processes of this important pathogen.