Ca2+-sensing transgenic mice -: Postsynaptic signaling in smooth muscle
Ca2+-sensing transgenic mice -: Postsynaptic signaling in smooth muscle
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DOI：
10.1074/jbc.m401084200
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发表时间：
2004-05-14
影响因子：
4.8
通讯作者：
Kotlikoff, MI
中科院分区：
文献类型：
--
作者：
Ji, GJ;Feldman, ME;Kotlikoff, MI
遗传编码的信号传导蛋白提供了设计和靶向表达可用于报告体内关键细胞事件的分子的显著机会，从而显著扩展了细胞功能研究的范围和生理相关性。在这里，我们报告的发展，转基因小鼠表达这样一个报告和使用它来检查突触后信号在平滑肌。环状排列的Ca 2+敏感分子G-CaMP（Nakai，J.，Ohkura，M.，和Imoto，K.等人（2001）Nat. Biotechnol. 19，137-141）在血管和非血管平滑肌中表达，并作为谱系特异性细胞内Ca 2+报告基因发挥作用。来自这些小鼠的逼尿肌组织用于识别由不同神经递质介导的两种不同类型的突触后Ca 2+信号。内源性神经刺激诱发快速的全细胞Ca 2+瞬变，或“Ca 2+闪光”，和缓慢传播的Ca 2+波。我们发现，Ca 2+闪光发生通过P2 X受体刺激和ryanodine受体介导的Ca 2+释放，而Ca 2+波产生的毒蕈碱受体刺激和肌醇三磷酸介导的Ca 2+释放。不同的亲离子型和亲代谢型突触后Ca ~（2+）信号在Ca ~（2+）释放水平上相关。重要的是，单个肌细胞能够进行突触后反应，并且在较高的突触输入下发生Ca 2+诱导的Ca 2+释放和三磷酸肌醇波之间的过渡。Ca 2+信号小鼠在进行性生物信号传导的研究中应提供显著的优势。
Genetically encoded signaling proteins provide remarkable opportunities to design and target the expression of molecules that can be used to report critical cellular events in vivo, thereby markedly extending the scope and physiological relevance of studies of cell function. Here we report the development of a transgenic mouse expressing such a reporter and its use to examine postsynaptic signaling in smooth muscle. The circularly permutated, Ca2+-sensing molecule G-CaMP (Nakai, J., Ohkura, M., and Imoto, K. (2001) Nat. Biotechnol. 19, 137-141) was expressed in vascular and non-vascular smooth muscle and functioned as a lineage-specific intracellular Ca2+ reporter. Detrusor tissue from these mice was used to identify two separate types of postsynaptic Ca2+ signals, mediated by distinct neurotransmitters. Intrinsic nerve stimulation evoked rapid, whole-cell Ca2+ transients, or "Ca2+ flashes," and slowly propagating Ca2+ waves. We show that Ca2+ flashes occur through P2X receptor stimulation and ryanodine receptor-mediated Ca2+ release, whereas Ca2+ waves arise from muscarinic receptor stimulation and inositol trisphosphate-mediated Ca2+ release. The distinct ionotropic and metabotropic postsynaptic Ca2+ signals are related at the level of Ca2+ release. Importantly, individual myocytes are capable of both postsynaptic responses, and a transition between Ca2+-induced Ca2+ release and inositol trisphosphate waves occurs at higher synaptic inputs. Ca2+ signaling mice should provide significant advantages in the study of processive biological signaling.