Secretory Expression of Human $\alpha_{s1}$-Casein in Saccharomyces cerevisiae

• Published in: Journal of microbiology and biotechnology Vol. 9; no. 2; pp. 196 - 200
• Main Authors: Kim, Yoo-Kyeong, Yu, Dae-Yeul, Kang, Hyun-Ah, Yoon, Sun, Chung, Bong-Hyun
• Format: Journal Article
• Language: Korean
• Published: 1999
• Subjects: leader sequence; secretion; Human $\alpha_{s1}$-casein; Saccharomyces cerevisiae; proteolysis
• ISSN: 1017-7825; 1738-8872

A recombinant human $\alpha_{s1}$-casein was expressed as a secretory product in the yeast Saccharomyces cerevisiae. Three different leader sequences derived from the mating factor $\alpha$l (MF$\alpha$l), inulinase, and human $\alpha_{s1}$-casein were used to direct the secretion of human $\alpha_{s1}$-casein into the extracellular medium. Among the three leader sequences tested, the native leader sequence of human $\alpha_{s1}$-casein was found to be the most efficient in the secretory expression of human $\alpha_{s1}$-casein, which implies that the native leader sequence of human $\alpha_{s1}$-casein might be used very efficiently for the secretory production of other heterologous proteins in yeast. The recombinant human $\alpha_{s1}$-casein was proteolytically cleaved as the culture proceeded. Therefore, an attempt was made to produce human $\alpha_{s1}$-casein using a S. cerevisiae mutant in which the YAP3 gene encoding yeast aspartic protease 3 (YAP3) was disrupted. After 72 h of culture, most of the human $\alpha_{s1}$-casein secreted by the wild type was cleaved, whereas more than 70% of the human $\alpha_{s1}$-casein secreted by yap3-disruptant remained intact. The results suggest that YAP3 might be involved in the internal cleavage of human $\alpha_{s1}$-casein expressed in yeast