Relationship of DFG16 to the Rim101p pH response pathway in Saccharomyces cerevisiae and Candida albicans
Relationship of DFG16 to the Rim101p pH response pathway in Saccharomyces cerevisiae and Candida albicans
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DOI：
10.1128/ec.4.5.890-899.2005
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发表时间：
2005-05-01
期刊：
影响因子：
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通讯作者：
Mitchell, AP
中科院分区：
文献类型：
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作者：
Barwell, KJ;Boysen, JH;Mitchell, AP
许多真菌的pH响应依赖于保守的Rim 101 p/PacC转录因子，其通过C-末端蛋白水解加工被激活。通过该途径感测环境pH的方法尚不清楚。在这里，我们报告了筛选的酿酒酵母可行的缺失突变体库，产生了一个新的基因所需的处理Rim 101 p的积累，DFG 16。色葡萄酿酒酵母dfg 16 δ突变体以升高的水平表达Rim 101 p抑制的基因。此外，白色念珠菌dfg 16 Delta/dfg 16 Delta突变体在碱性pH诱导的表达中有缺陷，并且它们的缺陷被截短的Rim 101 - 405 p的表达抑制。因此，Dfg 16 p是功能保守的Rim 101 p途径成员。Rim 101 p积累所需的许多蛋白质是ESCRT复合物的成员，其在多泡体（MVB）的形成中起作用。用染料FM 4 -64染色表明，S.酿酒酵母dfg 16 δ突变体不具有MVB缺陷。我们发现，PRY 1和ASN 1这两个转录本对影响Rim 101 p和MVB通路的突变有反应，但对只影响一个通路的突变没有反应。色葡萄酿酒酵母dfg 16 δ突变不影响PRY 1和ASN 1的表达，从而证实Dfg 16 p功能仅限于Rim 101 p途径。Dfg 16 p与构巢曲霉PalH同源，PalH是充分表征的PacC加工途径的组分。我们验证了先前公认的PalH同源物Rim 21 p也在S.酿酒酵母Rim 101 p途径。预测Dfg 16 p具有七个跨膜区段和一个长的亲水性C末端区域，如预期的，如果Dfg 16 p是G蛋白偶联受体。
Many fungal pH responses depend upon conserved Rim101p/PacC transcription factors, which are activated by C-terminal proteolytic processing. The means by which environmental pH is sensed by this pathway are not known. Here, we report a screen of the Saccharomyces cerevisiae viable deletion mutant library that has yielded a new gene required for processed Rim101p accumulation, DFG16. An S. cerevisiae dfg16 Delta mutant expresses Rim101p-repressed genes at elevated levels. In addition, Candida albicans dfg16 Delta/dfg16 Delta mutants are defective in alkaline pH-induced filamentation, and their defect is suppressed by expression of truncated Rim101-405p. Thus, Dfg16p is a functionally conserved Rim101p pathway member. Many proteins required for processed Rim101p accumulation are members of the ESCRT complex, which functions in the formation of multivesicular bodies (MVBs). Staining with the dye FM4-64 indicates that the S. cerevisiae dfg16 Delta mutant does not have an MVB defect. We find that two transcripts, PRY1 and ASN1, respond to mutations that affect both the Rim101p and MVB pathways but not to mutations that affect only one pathway. The S. cerevisiae dfg16 Delta mutation does not affect PRY1 and ASN1 expression, thus confirming that Dfg16p function is restricted to the Rim101p pathway. Dfg16p is homologous to Aspergillus nidulans PalH, a component of the well-characterized PacC processing pathway. We verify that the previously recognized PalH homolog, Rim21p, also functions in the S. cerevisiae Rim101p pathway. Dfg16p is predicted to have seven membrane-spanning segments and a long hydrophilic C-terminal region, as expected if Dfg16p were a G-protein-coupled receptor.