Oxygen-sensitive guanylyl cyclases in insects and their potential roles in oxygen detection and in feeding behaviors.
Oxygen-sensitive guanylyl cyclases in insects and their potential roles in oxygen detection and in feeding behaviors.
复制标题
昆虫中的氧敏感鸟苷酸环化酶及其在氧气检测和摄食行为中的潜在作用。
DOI：
10.1016/j.jinsphys.2005.12.001
复制
发表时间：
2006
影响因子：
2.2
通讯作者：
Morton,DavidB
中科院分区：
文献类型：
--
作者：
Vermehren,Anke;Langlais,KristoforK;Morton,DavidB
对缺氧和高氧的反应主要取决于动物检测O2水平变化的能力。然而，直到最近才在无脊椎动物中确定了O2传感系统。令人惊讶的是，越来越多的证据表明，这种分子O2传感器是一类被称为非典型sGC的可溶性鸟苷酸环化酶（sGC）。人们早就知道，传统的sGC α和β亚基形成异二聚体酶，这些酶被NO有效激活，但不结合O2。相比之下，果蝇非典型sGC亚基Gyc-88 E、Gyc-89 Da和Gyc-89 Db对NO仅轻微敏感，但在缺氧条件下被有效激活。在这里，我们审查的证据表明，非典型sGCs可以作为分子氧传感器介导的行为反应缺氧。其他预测的O2-敏感的sGC的序列比较表明，大多数，如果不是全部，昆虫表达两个异二聚体sGC;一个NO-敏感的亚型和一个单独的O2-敏感的亚型。表达数据和阻断表达非典型sGC的细胞的功能的最近实验以及降低这些细胞中cGMP水平的实验也表明了对甜味剂的行为反应中的作用。
Responses to hypoxia and hyperoxia depend critically on the ability of the animal to detect changes in O2levels. However, it has only been recently that an O2-sensing system has been identified in invertebrates. Evidence is accumulating that this molecular O2sensor is, surprisingly, a class of soluble guanylyl cyclase (sGC) known as atypical sGCs. It has long been known that the conventional sGC α and β subunits form heterodimeric enzymes that are potently activated by NO, but do not bind O2. By contrast, the Drosophila melanogaster atypical sGC subunits, Gyc-88E, Gyc-89Da and Gyc-89Db, are only slightly sensitive to NO, but are potently activated under hypoxic conditions. Here we review evidence that suggests that the atypical sGCs can function as molecular O2sensors mediating behavioral responses to hypoxia. Sequence comparisons of other predicted O2-sensitive sGCs suggest that most, if not all, insects express two heterodimeric sGCs; an NO-sensitive isoform and a separate O2-sensitive isoform. Expression data and recent experiments that block the function of cells that express the atypical sGCs and experiments that reduce the cGMP levels in these cells also suggest a role in behavioral responses to sweet tastants.