Crh1p and Crh2p are required for the cross-linking of chitin to β(1-6)glucan in the Saccharomyces cerevisiae cell wall
Crh1p and Crh2p are required for the cross-linking of chitin to β(1-6)glucan in the Saccharomyces cerevisiae cell wall
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DOI：
10.1111/j.1365-2958.2006.05565.x
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发表时间：
2007-02-01
影响因子：
3.6
通讯作者：
Arroyo, Javier
中科院分区：
文献类型：
--
作者：
Cabib, Enrico;Blanco, Noelia;Arroyo, Javier
在芽殖酵母中，几丁质存在于三个位置：在初生隔膜处，主要以游离形式存在;在母芽颈处，部分与β（1-3）葡聚糖连接;以及在侧壁中，部分与β（1-6）葡聚糖连接。通过使用最近开发的用于研究细胞壁交联的策略，我们发现，在CRH 1或CRH2/UTR 2基因的突变体中，与β（1-6）葡聚糖连接的几丁质减少，并且在双突变体中完全不存在。这表明Crh 1 p和Crh 2 p是糖基转移酶的同系物，将几丁质链从几丁质合成酶III转运到β（1-6）葡聚糖。CRH 1和/或CRH2的缺失加重了fks 1 Delta和gas 1 Delta突变体的缺陷，这些突变体在细胞壁合成中受损。从30摄氏度到38摄氏度的温度变化增加了附着于β（1-6）葡聚糖的几丁质的比例。CRH 1的表达，而不是CRH2的表达，在38 ℃下也以依赖于细胞完整性途径的方式更高。此外，Crh 1 p和Crh 2 p在细胞皮层（发现几丁质-β（1-6）葡聚糖复合物的区域）的定位在38 ℃时大大增强。Crh 1 p和Crh 2 p是第一个直接参与真菌细胞壁组分之间交联形成的蛋白质。
In budding yeast, chitin is found in three locations: at the primary septum, largely in free form, at the mother-bud neck, partially linked to beta(1-3)glucan, and in the lateral wall, attached in part to beta(1-6)glucan. By using a recently developed strategy for the study of cell wall cross-links, we have found that chitin linked to beta(1-6)glucan is diminished in mutants of the CRH1 or the CRH2/UTR2 gene and completely absent in a double mutant. This indicates that Crh1p and Crh2p, homologues of glycosyltransferases, ferry chitin chains from chitin synthase III to beta(1-6)glucan. Deletion of CRH1 and/or CRH2 aggravated the defects of fks1 Delta and gas1 Delta mutants, which are impaired in cell wall synthesis. A temperature shift from 30 degrees C to 38 degrees C increased the proportion of chitin attached to beta(1-6)glucan. The expression of CRH1, but not that of CRH2, was also higher at 38 degrees C in a manner dependent on the cell integrity pathway. Furthermore, the localization of both Crh1p and Crh2p at the cell cortex, the area where the chitin-beta(1-6)glucan complex is found, was greatly enhanced at 38 degrees C. Crh1p and Crh2p are the first proteins directly implicated in the formation of cross-links between cell wall components in fungi.