科學家首次實現納米尺度下的cAMP信號成像
作者:
小柯機器人發布時間:2020/8/27 14:41:28
德國馬普研究所Martin J. Lohse、Andreas Bock等研究人員合作實現在納米尺度下cAMP信號的光學成像。2020年8月25日,國際知名學術期刊《細胞》在線發表了這一成果。
研究人員表示,細胞僅使用少數幾個第二信使(例如cAMP)就將大量胞外信號傳遞給特定的細胞反應。為了解釋信號傳導的特異性,已經有研究提出了降解cAMP的磷酸二酯酶(PDE)可將cAMP限制在不同的細胞區室中。但是,已測量到的cAMP快速擴散速率和PDE緩慢活性速率使cAMP分隔基本上不可能。
使用螢光光譜,研究人員發現,與早期的數據相反,生理濃度下的cAMP主要與cAMP結合位點結合,因此不可移動。綁定和解除綁定會大大降低cAMP動態,研究人員稱之為「緩衝擴散」。通過對大部分cAMP進行緩衝,PDE可以創建低cAMP濃度的納米域。使用FRET-cAMP納米尺,研究人員可以直接在PDE分子周圍的納米尺度上繪製cAMP梯度,並繪製出cAMP依賴性蛋白激酶(PKA)的下遊激活區域。
這些研究表明,時空cAMP信號傳導受門控下遊效應子激活的PDE納米域的精確控制。
附:英文原文
Title: Optical Mapping of cAMP Signaling at the Nanometer Scale
Author: Andreas Bock, Paolo Annibale, Charlotte Konrad, Annette Hannawacker, Selma E. Anton, Isabella Maiellaro, Ulrike Zabel, Sivaraj Sivaramakrishnan, Martin Falcke, Martin J. Lohse
Issue&Volume: 2020-08-25
Abstract: Cells relay a plethora of extracellular signals to specific cellular responses byusing only a few second messengers, such as cAMP. To explain signaling specificity,cAMP-degrading phosphodiesterases (PDEs) have been suggested to confine cAMP to distinctcellular compartments. However, measured rates of fast cAMP diffusion and slow PDEactivity render cAMP compartmentalization essentially impossible. Using fluorescencespectroscopy, we show that, contrary to earlier data, cAMP at physiological concentrationsis predominantly bound to cAMP binding sites and, thus, immobile. Binding and unbindingresults in largely reduced cAMP dynamics, which we term 「buffered diffusion.」 Witha large fraction of cAMP being buffered, PDEs can create nanometer-size domains oflow cAMP concentrations. Using FRET-cAMP nanorulers, we directly map cAMP gradientsat the nanoscale around PDE molecules and the areas of resulting downstream activationof cAMP-dependent protein kinase (PKA). Our study reveals that spatiotemporal cAMPsignaling is under precise control of nanometer-size domains shaped by PDEs that gateactivation of downstream effectors.
DOI: 10.1016/j.cell.2020.07.035
Source: https://www.cell.com/cell/fulltext/S0092-8674(20)30943-0
Cell:《細胞》,創刊於1974年。隸屬於細胞出版社,最新IF:36.216