近日，來(lái)自歐洲分子生物學(xué)實(shí)驗(yàn)室的研究者通過(guò)將兩種不同類(lèi)型的顯微技術(shù)結(jié)合起來(lái)開(kāi)發(fā)出了“3D電影技術(shù)”來(lái)觀(guān)察細(xì)胞如何內(nèi)吞營(yíng)養(yǎng)物以及其它分子,。相關(guān)研究刊登在了近日的國(guó)際雜志Cell上,。
細(xì)胞這種“吞咽作用”稱(chēng)為細(xì)胞吞噬現(xiàn)象，是細(xì)胞完成的至關(guān)重要的任務(wù),。這個(gè)過(guò)程可以被許多病毒“劫持”,，從而使得病毒達(dá)到侵染宿主細(xì)胞的目的。當(dāng)細(xì)胞準(zhǔn)備吞咽一些分子的時(shí)候,，細(xì)胞膜表面會(huì)產(chǎn)生凹陷,，逐漸地向內(nèi)擴(kuò)張,，擠壓斷裂形成小包或者膜泡,，從而將分子轉(zhuǎn)移入細(xì)胞內(nèi)部。
為了研究細(xì)胞如何牽引細(xì)胞膜并且形成小囊泡的,，研究者基于光學(xué)顯微鏡和高分辨率顯微鏡技術(shù)開(kāi)發(fā)了一種方法,，這種新方法可以使研究者結(jié)合兩組數(shù)據(jù)來(lái)分析細(xì)胞是如何完成這個(gè)過(guò)程的,。研究者發(fā)現(xiàn)第一個(gè)蛋白質(zhì)達(dá)到細(xì)胞膜內(nèi)部并不能夠使得細(xì)胞膜回折，直到細(xì)胞支架蛋白-肌動(dòng)蛋白網(wǎng)絡(luò)形成以后才會(huì)開(kāi)始彎折,。
后期研究者將為這個(gè)過(guò)程中的蛋白質(zhì)進(jìn)行標(biāo)記,，通過(guò)打亂這些蛋白質(zhì)研究者希望延伸一下當(dāng)前的工作。（生物谷Bioon.com）
編譯自：3D movie at 'ultraresolution' shows how cell’s machinery bends membrane inwards
doi:10.1016/j.cell.2012.05.046
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Plasma Membrane Reshaping during Endocytosis Is Revealed by Time-Resolved Electron Tomography
Wanda Kukulski, Martin Schorb, Marko Kaksonen, John A.G. Briggs
Endocytosis, like many dynamic cellular processes, requires precise temporal and spatial orchestration of complex protein machinery to mediate membrane budding. To understand how this machinery works, we directly correlated fluorescence microscopy of key protein pairs with electron tomography. We systematically located 211 endocytic intermediates, assigned each to a specific time window in endocytosis, and reconstructed their ultrastructure in 3D. The resulting virtual ultrastructural movie defines the protein-mediated membrane shape changes during endocytosis in budding yeast. It reveals that clathrin is recruited to flat membranes and does not initiate curvature. Instead, membrane invagination begins upon actin network assembly followed by amphiphysin binding to parallel membrane segments, which promotes elongation of the invagination into a tubule. Scission occurs on average 9 s after initial bending when invaginations are ∼100 nm deep, releasing nonspherical vesicles with 6,400 nm2 mean surface area. Direct correlation of protein dynamics with ultrastructure provides a quantitative 4D resource.
