Gpr1, a putative G-protein-coupled receptor, regulates morphogenesis and hypha formation in the pathogenic fungus Candida albicans
Gpr1, a putative G-protein-coupled receptor, regulates morphogenesis and hypha formation in the pathogenic fungus Candida albicans
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DOI：
10.1128/ec.3.4.919-931.2004
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发表时间：
2004-08-01
期刊：
影响因子：
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通讯作者：
Tamaki, H
中科院分区：
文献类型：
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作者：
Miwa, T;Takagi, Y;Tamaki, H
响应各种细胞外信号，人类真菌病原体白色念珠菌的形态。从酵母到菌丝形态的转换。在这里，我们报道GPR1编码一个假定的G蛋白偶联受体，GPA2编码一个G(x)亚基是白色念珠菌菌丝形成和形态发生所必需的。缺乏Gpr1 （Gpr1 / Gpr1）或Gpa2 （Gpa2 / Gpa2）的突变体在固体菌丝诱导培养基上菌丝形成和形态发生缺陷。这些表型缺陷在固体培养中被外源添加的二丁基环AMP （dibutyryi-cAMP）抑制。生化研究还表明，GPR1和GPA2是葡萄糖依赖性细胞cAMP增加所必需的。上位性分析表明Gpr1在Gpa2的上游发挥作用，双杂交实验表明Gpr1的羧基末端尾部与Gpa2相互作用。此外，在两种突变菌株中，camp依赖性菌丝特异性基因HWP1和ECE1的表达水平都有所降低。这些发现支持了Gpr1和Gpa2以camp依赖的方式调节菌丝形成和形态发生的模型。相比之下，在液态胎牛血清（FBS）培养基中，菌丝形成不需要GPR1和GPA2。此外，gprI和gpa2突变株在小鼠感染中具有完全毒力。这些发现表明，Gpr1和Gpa2通过camp依赖机制参与了固体培养基中葡萄糖感应机制的形态发生和菌丝形成的调节，但它们不是液体培养基或侵袭性念珠菌病中菌丝形成所必需的。
In response to various extracellular signals, the morphology of the human fungal pathogen Candida albicans. switches from yeast to hypha form. Here, we report that GPR1 encoding a putative G-protein-coupled receptor and GPA2 encoding a G(x subunit are required for hypha formation and morphogenesis in C albicans. Mutants lacking Gpr1 (gpr1/gpr1) or Gpa2 (gpa2/gpa2) are defective in hypha formation and morphogenesis on solid hypha-inducing media. These phenotypic defects in solid cultures are suppressed by exogenously added dibutyryl-cyclic AMP (dibutyryi-cAMP). Biochemical studies also reveal that GPR1 and GPA2 are required for a glucose-dependent increase in cellular cAMP. An epistasis analysis indicates that Gpr1 functions upstream of Gpa2 in the same signaling pathway, and a two-hybrid assay reveals that the carboxyl-terminal tail of Gpr1 interacts with Gpa2. Moreover, expression levels of HWP1 and ECE1, which are cAMP-dependent hyphaspecific genes, are reduced in both mutant strains. These findings support a model that Gpr1, as well as Gpa2, regulates hypha formation and morphogenesis in a cAMP-dependent manner. In contrast, GPR1 and GPA2 are not required for hypha formation in liquid fetal bovine serum (FBS) medium. Furthermore, the gprI and the gpa2 mutant strains are fully virulent in a mouse infection. These findings suggest that Gpr1 and Gpa2 are involved in the glucose-sensing machinery that regulates morphogenesis and hypha formation in solid media via a cAMP-dependent mechanism, but they are not required for hypha formation in liquid medium or during invasive candidiasis.