Sepúlveda-González M Eugenia, Parra-Ortega Berenice, Betancourt-Cervantes Yuliana, Hernández-Rodríguez César, Xicohtencatl-Cortes Juan, Villa-Tanaca Lourdes
Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas del Instituto Politécnico Nacional, Delegación Miguel Hidalgo, México, D.F., Mexico; Laboratorio de Investigación en Bacteriología Intestinal, Unidad de Hemato-Oncología e Investigación, Hospital Infantil de México Federico Gómez, Delegación Cuauhtémoc, México, D.F., Mexico.
Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas del Instituto Politécnico Nacional, Delegación Miguel Hidalgo, México, D.F., Mexico.
Rev Iberoam Micol. 2016 Jan-Mar;33(1):26-33. doi: 10.1016/j.riam.2014.10.005. Epub 2015 Jul 16.
The Saccharomyces cerevisiae vacuole is actively involved in the mechanism of autophagy and is important in homeostasis, degradation, turnover, detoxification and protection under stressful conditions. In contrast, vacuolar proteases have not been fully studied in phylogenetically related Candida glabrata.
The present paper is the first report on proteolytic activity in the C. glabrata vacuole.
Biochemical studies in C. glabrata have highlighted the presence of different kinds of intracellular proteolytic activity: acid aspartyl proteinase (PrA) acts on substrates such as albumin and denatured acid hemoglobin, neutral serine protease (PrB) on collagen-type hide powder azure, and serine carboxypeptidase (CpY) on N-benzoyl-tyr-pNA.
Our results showed a subcellular fraction with highly specific enzymatic activity for these three proteases, which allowed to confirm its vacuolar location. Expression analyses were performed in the genes CgPEP4 (CgAPR1), CgPRB1 and CgCPY1 (CgPRC), coding for vacuolar aspartic protease A, neutral protease B and carboxypeptidase Y, respectively. The results show a differential regulation of protease expression depending on the nitrogen source.
The proteases encoded by genes CgPEP4, CgPRB1 and CgCPY1 from C. glabrata could participate in the process of autophagy and survival of this opportunistic pathogen.
酿酒酵母液泡积极参与自噬机制，在应激条件下的稳态、降解、周转、解毒和保护过程中发挥重要作用。相比之下，在系统发育相关的光滑念珠菌中，液泡蛋白酶尚未得到充分研究。
本文首次报道了光滑念珠菌液泡中的蛋白水解活性。
对光滑念珠菌的生化研究突出了不同种类细胞内蛋白水解活性的存在：酸性天冬氨酸蛋白酶（PrA）作用于白蛋白和变性酸性血红蛋白等底物，中性丝氨酸蛋白酶（PrB）作用于胶原型皮粉天青，丝氨酸羧肽酶（CpY）作用于N-苯甲酰-酪氨酰-对硝基苯胺。
我们的结果显示了一个对这三种蛋白酶具有高度特异性酶活性的亚细胞部分，这证实了其液泡定位。对分别编码液泡天冬氨酸蛋白酶A、中性蛋白酶B和羧肽酶Y的CgPEP4（CgAPR1）、CgPRB1和CgCPY1（CgPRC）基因进行了表达分析。结果表明，蛋白酶表达的调控因氮源而异。
光滑念珠菌中由CgPEP4、CgPRB1和CgCPY1基因编码的蛋白酶可能参与了这种机会性病原体的自噬和存活过程。
