美國(guó)約翰•霍普金斯大學(xué)的Wang等研究發(fā)現(xiàn),，磷酸肌醇特異性磷脂酶C (PLC) 的同工酶在果蠅的光轉(zhuǎn)錄等的多個(gè)過程中發(fā)揮作用,。在果蠅的感光細(xì)胞中,，由NORPA編碼的PLCβ對(duì)TRP通道的激活起到關(guān)鍵作用,。Wang等描述的PLCβ調(diào)節(jié)器——STOPS,，編碼了一種SOCS盒型蛋白質(zhì),。STOPS的基因突變會(huì)導(dǎo)致NORPA的濃度降低,，以及光刺激消失后光感停止信號(hào)的缺失,。
以往的研究認(rèn)為NORPA有作為PLC激活蛋白和GTP酶激活蛋白的雙重作用。Wang等認(rèn)為,，由于野生型NORPA的低水平表達(dá)導(dǎo)致的光感反映的緩慢停止現(xiàn)象,，可以通過加入正常量的改造NORPA來抑制。這種改造后的NORPA有野生型GAP的活性,，但沒有PLC的活性,。
STOPS是迄今發(fā)現(xiàn)的可以特異性調(diào)節(jié)PLCβ蛋白濃度的第一個(gè)蛋白質(zhì)。這項(xiàng)研究同時(shí)也表明,，在體內(nèi),，PLCβ的衍生物沒有激活TRP通道的作用，只有傳遞信號(hào)的作用,。
相關(guān)研究論文發(fā)表在2008年1月10日的《神經(jīng)元》（Neuron）上,。（科學(xué)網(wǎng) 武彥文/編譯）
（《神經(jīng)元》（Neuron），Vol 57, 56-68, 10 January 2008,，Tao Wang, Craig Montell）
生物谷推薦原始出處：
Neuron, Vol 57, 56-68, 10 January 2008
Article
The SOCS Box Protein STOPS Is Required for Phototransduction through Its Effects on Phospholipase C
Tao Wang,1,3 Xiaoyue Wang,1,3 Qiang Xie,2 and Craig Montell1,
1 Departments of Biological Chemistry and Neuroscience, Center for Sensory Biology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
2 School of Optometry, Indiana University, Bloomington, IN 47405, USA
Corresponding author
Craig Montell
[email protected]
Summary
Phosphoinositide-specific phospholipase C (PLC) isozymes play roles in a diversity of processes including Drosophila phototransduction. In fly photoreceptor cells, the PLCβ encoded by norpA is critical for activation of TRP channels. Here, we describe a PLCβ regulator, STOPS, which encodes a SOCS box protein. Mutation of stops resulted in a reduced concentration of NORPA and a defect in stopping signaling following cessation of the light stimulus. NORPA has been proposed to have dual roles as a PLC- and GTPase-activating protein (GAP). We found that the slow termination resulting from expressing low levels of wild-type NORPA was suppressed by addition of normal amounts of an altered NORPA, which had wild-type GAP activity, but no PLC activity. STOPS is the first protein identified that specifically regulates PLCβ protein concentration. Moreover, this work demonstrates that a PLCβ derivative that does not promote TRP channel activation, still contributes to signaling in vivo.
