Taylor Colin W, Prole David L
Department of Pharmacology, Tennis Court Road, CB2 1PD, Cambridge, UK,
Subcell Biochem. 2012;59:1-34. doi: 10.1007/978-94-007-3015-1_1.
The Ca(2) (+) signals evoked by inositol 1,4,5-trisphosphate (IP(3)) are built from elementary Ca(2) (+) release events involving progressive recruitment of IP(3) receptors (IP(3)R), intracellular Ca(2) (+) channels that are expressed in almost all animal cells. The smallest events ('blips') result from opening of single IP(3)R. Larger events ('puffs') reflect the near-synchronous opening of a small cluster of IP(3)R. These puffs become more frequent as the stimulus intensity increases and they eventually trigger regenerative Ca(2) (+) waves that propagate across the cell. This hierarchical recruitment of IP(3)R is important in allowing Ca(2) (+) signals to be delivered locally to specific target proteins or more globally to the entire cell. Co-regulation of IP(3)R by Ca(2) (+) and IP(3), the ability of a single IP(3)R rapidly to mediate a large efflux of Ca(2) (+) from the endoplasmic reticulum, and the assembly of IP(3)R into clusters are key features that allow IP(3)R to propagate Ca(2) (+) signals regeneratively. We review these properties of IP(3)R and the structural basis of IP(3)R behavior.
由肌醇1,4,5 - 三磷酸（IP(3)）诱发的Ca(2)+信号是由基本的Ca(2)+释放事件构建而成的，这些事件涉及IP(3)受体（IP(3)R）的逐步募集，IP(3)R是几乎在所有动物细胞中都有表达的细胞内Ca(2)+通道。最小的事件（“尖峰”）是由单个IP(3)R的开放引起的。较大的事件（“阵发”）反映了一小簇IP(3)R的近乎同步开放。随着刺激强度的增加，这些阵发变得更加频繁，最终触发在整个细胞中传播的再生性Ca(2)+波。IP(3)R的这种分级募集对于使Ca(2)+信号能够局部传递到特定的靶蛋白或更广泛地传递到整个细胞很重要。Ca(2)+和IP(3)对IP(3)R的共同调节、单个IP(3)R迅速介导内质网中大量Ca(2)+外流的能力以及IP(3)R聚集成簇是使IP(3)R能够再生性地传播Ca(2)+信号的关键特征。我们综述了IP(3)R的这些特性以及IP(3)R行为的结构基础。
