Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China.
Medical Mycology Research Center, Chiba University, Chiba, Japan.
Yeast. 2020 Jul;37(7-8):359-371. doi: 10.1002/yea.3502. Epub 2020 Jun 24.
In the budding yeast Saccharomyces cerevisiae, Svl3 and Pam1 proteins work as functional homologues. Loss of their function causes increased levels of chitin deposition in the cell wall and temperature sensitivity, suggesting their involvement in cell wall formation. We found that the N- and C-termini of these proteins have distinctive and critical functions. They contain an N-terminal part that has a probable 2-dehydropantoate 2-reductase domain. In Svl3, this part can be replaced with the yeast 2-dehydropantoate 2-reductase, Pan5, suggesting that Svl3 and its homologues may be able to mediate 2-dehydropantoate 2-reductase function. On the other hand, Svl3 is recruited to the bud tip and bud neck via multiple localization signals in the C-terminal part. One of such signals is the lysine-rich region located in the C-terminal end. The function and localization of Svl3 are significantly disrupted by the loss of this lysine-rich region; however, its localization is not completely abolished by the mutation because another localization signal enables appropriate transport. Svl3 and Pam1 orthologues are found in cells across fungal species. The Svl3 orthologues of Candida glabrata can complement the loss of Svl3 and Pam1 in S. cerevisiae. C. glabrata cells lacking the SVL3 and PAM1 orthologue genes exhibit phenotypes similar to those observed in svl3∆pam1∆ S. cerevisiae cells. Thus, Svl3 homologues may be generally required for the assembly of the cell wall in fungal cells.
在 budding 酵母酿酒酵母中，Svl3 和 Pam1 蛋白作为功能同源物发挥作用。它们功能的丧失会导致细胞壁中几丁质沉积增加和对温度敏感，表明它们参与了细胞壁的形成。我们发现这些蛋白质的 N-和 C-末端具有独特且关键的功能。它们包含一个可能具有 2-脱水葡萄糖酸 2-还原酶结构域的 N-端部分。在 Svl3 中，这个部分可以被酵母 2-脱水葡萄糖酸 2-还原酶 Pan5 取代，这表明 Svl3 和它的同源物可能能够介导 2-脱水葡萄糖酸 2-还原酶的功能。另一方面，Svl3 通过 C-末端的多个定位信号被招募到芽尖和芽颈。这些信号之一是位于 C-末端的富含赖氨酸的区域。这个富含赖氨酸的区域的缺失会严重破坏 Svl3 的功能和定位；然而，由于另一个定位信号能够使 Svl3 进行适当的运输，所以它的定位并没有完全被破坏。Svl3 和 Pam1 的同源物存在于真菌细胞中。假丝酵母 Candida glabrata 的 Svl3 同源物可以弥补酿酒酵母 Svl3 和 Pam1 的缺失。缺乏 SVL3 和 PAM1 同源基因的 C. glabrata 细胞表现出与 svl3∆pam1∆ S. cerevisiae 细胞中观察到的相似表型。因此，Svl3 同源物可能普遍需要用于真菌细胞细胞壁的组装。
