Poels Jeroen, Vanden Broeck Jozef
Laboratory for Developmental Physiology, Genomics and Proteomics, Catholic University Leuven, B-3000 Leuven, Belgium.
Int Rev Cytol. 2004;241:277-309. doi: 10.1016/S0074-7696(04)41005-5.
The cAMP-protein kinase A (PKA) pathway is an important intracellular signal transduction cascade that can be activated by a large variety of stimuli. Activation or inhibition of this pathway will ultimately affect the transcriptional regulation of various genes through distinct responsive sites. In vertebrates, the best- characterized nuclear targets of PKA are the cyclic AMP response element-binding (CREB) proteins. It is now well established that CREB is not only regulated by PKA, but many other kinases can exert an effect as well. Since CREB-like proteins were also discovered in invertebrates, several studies unraveling their physiological functions in this category of metazoans have been performed. This review will mainly focus on the presence and regulation of CREB proteins in insects. Differences in transcriptional responses to the PKA pathway and other CREB-regulating stimuli between cells, tissues, and even organisms can be partially attributed to the presence of different CREB isoforms. In addition, the regulation of CREB appears to show some important differences between insects and vertebrates. Since CREB is a basic leucine zipper (bZip) protein, other insect members of this important family of transcriptional regulators will be briefly discussed as well.
环磷酸腺苷-蛋白激酶A（PKA）信号通路是一种重要的细胞内信号转导级联反应，可被多种刺激激活。该信号通路的激活或抑制最终会通过不同的反应位点影响各种基因的转录调控。在脊椎动物中，PKA最典型的核靶点是环磷酸腺苷反应元件结合（CREB）蛋白。目前已经明确，CREB不仅受PKA调控，许多其他激酶也能发挥作用。由于在无脊椎动物中也发现了类似CREB的蛋白，因此已经开展了多项研究来揭示它们在这类后生动物中的生理功能。本综述将主要关注昆虫中CREB蛋白的存在及调控情况。细胞、组织甚至生物体对PKA信号通路和其他CREB调控刺激的转录反应差异，部分可归因于不同CREB亚型的存在。此外，CREB的调控在昆虫和脊椎动物之间似乎存在一些重要差异。由于CREB是一种碱性亮氨酸拉链（bZip）蛋白，本文还将简要讨论这一重要转录调节因子家族的其他昆虫成员。
