Cross-talk between cAMP and calcium signalling in Aspergillus niger
Cross-talk between cAMP and calcium signalling in Aspergillus niger
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DOI：
10.1111/j.1365-2958.2005.04541.x
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发表时间：
2005-04-01
影响因子：
3.6
通讯作者：
Read, ND
中科院分区：
文献类型：
--
作者：
Bencina, M;Legisa, M;Read, ND
关于丝状真菌中 cAMP 和钙信号传导之间的串扰知之甚少。本研究的目的是分析黑曲霉中 cAMP 和蛋白激酶 A (PKA) 依赖性磷酸化对钙信号传导的影响。为此目的，在表达密码子优化的水母发光蛋白的活菌丝中测量胞质游离钙（[Ca2+](c)）。在应用二丁酰-cAMP或IBMX（增加细胞内cAMP）或H7（抑制PKA磷酸化）后，分析机械扰动后的钙信号。还测量了 PKA 磷酸化增加或缺乏的突变株中的钙特征。结果表明，钙通道是由 cAMP 介导的、PKA 依赖性磷酸化激活的。 cAMP 和钙信号传导之间串扰的进一步证据来自对突变体的分析，其中 PKA 的催化亚基受到诱导型启动子的控制。 PKA 诱导的结果是 [Ca2+](c) 短暂增加，这与菌丝形态的极性-非极性转变相关。当形态转变朝相反方向时，在此突变体中未观察到 [Ca2+](c) 短暂增加。极化和非极化细胞响应机械扰动的 [Ca2+](c) 特征明显不同，表明这两种细胞类型具有不同的钙信号传导能力。这些结果与 PKA 依赖性磷酸化增加 [Ca2+](c) 诱导菌丝形态从极性到非极性的转变一致。
Very little is known about cross-talk between cAMP and calcium signalling in filamentous fungi. The aim of this study was to analyse the influence of cAMP and protein kinase A (PKA)-dependent phosphorylation on calcium signalling in Aspergillus niger. For this purpose, cytosolic free calcium ([Ca2+](c)) was measured in living hyphae expressing codon-optimized aequorin. The calcium signature following mechanical perturbation was analysed after applying dibutryl-cAMP or IBMX which increased intracellular cAMP, or H7 which inhibited phosphorylation by PKA. Calcium signatures were also measured in mutant strains in which phosphorylation by PKA was increased or lacking. The results indicated that calcium channels were activated by cAMP-mediated, PKA-dependent phosphorylation. Further evidence for cross-talk between cAMP and calcium signalling came from the analysis of a mutant in which the catalytic subunit of PKA was under the control of an inducible promoter. The consequence of PKA induction was a transient increase in [Ca2+](c) which correlated with a polar-apolar transition in hyphal morphology. A transient increase in [Ca2+](c) was not observed in this mutant when the morphological shift was in the opposite direction. The [Ca2+](c) signatures in response to mechanical perturbation by polarized and unpolarized cells were markedly different indicating that these two cell types possessed different calcium signalling capabilities. These results were consistent with PKA-dependent phosphorylation increasing [Ca2+](c) to induce a polar to apolar shift in hyphal morphology.