Matange Nishad
Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pune 411008, India
FEMS Microbiol Lett. 2015 Nov;362(22). doi: 10.1093/femsle/fnv183. Epub 2015 Sep 30.
Cyclic-3',5'-adenosine monophosphate (cAMP) is a universal second messenger that regulates vital activities in bacteria and eukaryotes. Enzymes that hydrolyze cAMP, called phosphodiesterases (PDEs), negatively regulate the levels of this messenger molecule and are therefore crucial for signal 'termination'. In this minireview, I shall summarize the available literature on bacterial cAMP-PDEs, with particular emphasis on enzymes belonging to the ubiquitously encoded Class III PDE family exemplified by CpdA from Escherichia coli and Rv0805 from Mycobacterium tuberculosis. Using available biochemical, structural and biological information, I shall make a case for re-examining the functions of these enzymes as merely regulators of intrabacterial cAMP levels and suggest that some members of this class may have evolved cAMP-independent functions as well. Finally, I shall highlight the major lacunae in our understanding of these enzymes and present unanswered questions in the area.
环磷腺苷（cAMP）是一种通用的第二信使，可调节细菌和真核生物的重要生命活动。水解cAMP的酶称为磷酸二酯酶（PDE），它对这种信使分子的水平起负调节作用，因此对信号“终止”至关重要。在这篇小型综述中，我将总结关于细菌cAMP-PDE的现有文献，特别强调属于普遍编码的III类PDE家族的酶，以大肠杆菌的CpdA和结核分枝杆菌的Rv0805为例。利用现有的生化、结构和生物学信息，我将提出重新审视这些酶仅作为细菌内cAMP水平调节剂的功能，并表明该类中的一些成员可能也进化出了不依赖cAMP的功能。最后，我将强调我们对这些酶理解中的主要空白，并提出该领域尚未解决的问题。
