香港科技大學２７日發(fā)布消息,，其生命科學部客座教授張明杰及其團隊對動物偵測光的視覺系統(tǒng)研究取得重大突破,。該突破對研究視網(wǎng)膜色素變性及其他人類視覺障礙將有很大幫助,。
據(jù)介紹,，每３０００人就有一人患有視網(wǎng)膜色素變性,，其早期病癥表現(xiàn)為夜盲,。此外,，科大研究團隊的最新成果對于了解人類的癌癥,、神經(jīng)退化及免疫力障礙等疾病的生物信號轉(zhuǎn)導過程也有幫助。
科大的消息說,，２４日出版的最新一期生命科學界頂級權(quán)威雜志《細胞》,，選取了這一研究作為封面文章。
據(jù)介紹,，過去數(shù)十年來科學家一直努力研究動物視覺系統(tǒng)的機理,，譬如動物如何在黑夜、強烈日光及其他情況下偵測光,，及人類眼睛如何于不同的光度環(huán)境下作出反應并調(diào)控光的接收,。大部分動物都有視覺偵測系統(tǒng)，即不同形態(tài)的感光細胞,，盡管這些感光細胞的設(shè)計與目的各有不同,，但它們吸收光信號（或光子）轉(zhuǎn)化為視覺反應（或電子反應）的機理卻十分相似。
張明杰教授及其研究團隊利用果蠅的感光細胞作為模型系統(tǒng),，研究出動物的感光細胞如何以極高的速度偵測強度差距極大的光信號,。
張明杰教授表示，人類以及蒼蠅等昆蟲的視覺系統(tǒng)能夠以幾十毫秒至幾百毫秒的高速在差異很大的環(huán)境內(nèi)偵測光線的存在，如果在這些方面有所缺憾,，后果不堪設(shè)想,。譬如說，如果人類不能在不到一秒的時間內(nèi)對高速駛來的車輛有所反應,，或者蒼蠅不能夠于一瞬間偵測到迎面而來的蒼蠅拍,，便會閃避不及。（生物谷Bioon.com）
生物谷推薦原文出處：
Cell DOI：10.1016/j.cell.2011.05.015
The INAD Scaffold Is a Dynamic, Redox-Regulated Modulator of Signaling in the Drosophila Eye
Wei Liu, Wenyu Wen, Zhiyi Wei, Jiang Yu, Fei Ye, Che-Hsiung Liu, Roger C. Hardie, Mingjie Zhang
INAD is a scaffolding protein that regulates signaling in Drosophila photoreceptors. One of its PDZ domains, PDZ5, cycles between reduced and oxidized forms in response to light, but it is unclear how light affects its redox potential. Through biochemical and structural studies, we show that the redox potential of PDZ5 is allosterically regulated by its interaction with another INAD domain, PDZ4. Whereas isolated PDZ5 is stable in the oxidized state, formation of a PDZ45 supramodule locks PDZ5 in the reduced state by raising the redox potential of its Cys606/Cys645 disulfide bond by 330 mV. Acidification, potentially mediated via light and PLCβ-mediated hydrolysis of PIP2, disrupts the interaction between PDZ4 and PDZ5, leading to PDZ5 oxidation and dissociation from the TRP Ca2+ channel, a key component of fly visual signaling. These results show that scaffolding proteins can actively modulate the intrinsic redox potentials of their disulfide bonds to exert regulatory roles in signaling.
