A Myxococcus xanthus CbpB containing two cAMP-binding domains is involved in temperature and osmotic tolerances.
A Myxococcus xanthus CbpB containing two cAMP-binding domains is involved in temperature and osmotic tolerances.
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DOI：
10.1016/j.femsle.2005.01.027
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发表时间：
2005-03
影响因子：
2.1
通讯作者：
Y. Kimura;H. Nakato;K. Ishibashi;S. Kobayashi
中科院分区：
文献类型：
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作者：
Y. Kimura;H. Nakato;K. Ishibashi;S. Kobayashi
我们的前期研究表明，黄色粘球菌腺苷酸环化酶（Myxococcus xanthussensor-type adenylyl cyclase，CyaA）在渗透胁迫下的信号转导中起重要作用。然而，cAMP介导的信号转导途径在这种细菌是未知的。在这里，我们从aM中分离出一个克隆。xanthusgenomic DNA文库使用基于cAMP依赖性蛋白激酶（PKA）调节亚基的保守cAMP结合结构域设计的寡核苷酸探针。该克隆含有两个开放阅读框（ORF）cbpA和cbpB，分别编码一个和两个cAMP结合结构域的亲水性蛋白。CbpB与PKA调控亚基具有部分一级结构相似性，通过基因破坏产生的cbpA和cbpB突变体表现出正常的生长发育和孢子萌发。然而，在高温或低温条件下培养的cbpB突变体表现出明显的生长下降。cbpB突变体细胞也比野生型细胞对渗透胁迫更敏感。ecbpA突变体具有正常的抗性。cbpB突变体的表型与某些真核微生物PKA调节亚基突变体的表型相似。
Our previous data indicated that aMyxococcus xanthussensor-type adenylyl cyclase (CyaA) functions in signal transduction during osmotic stress. However, the cAMP-mediated signal transduction pathway in this bacterium was unknown. Here, we isolated a clone from aM. xanthusgenomic DNA library using oligonucleotide probes designed based on the conserved cAMP-binding domains of the cAMP-dependent protein kinase (PKA) regulatory subunits. The clone contained two open-reading frames (ORFs),cbpAandcbpB, encoding hydrophilic proteins with one and two cAMP-binding domains, respectively. The CbpB exhibited partial primary structural similarity to PKA regulatory subunits.cbpAandcbpBmutants, generated by gene disruption, showed normal growth, development and spore germination. However, thecbpBmutant cultured under high- or low-temperature conditions exhibited a marked reduction in growth.cbpBmutant cells were also more sensitive to osmotic stress than wild-type cells. ThecbpAmutant possessed normal resistance to such stress. The phenotype ofcbpBmutant was similar to those of PKA regulatory subunit mutants of some eukaryotic microorganisms.