Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
Department of Plant Biology, Michigan State University, East Lansing, MI 48824, USA; MSU-DOE Plant Research Lab, Michigan State University, East Lansing, MI 48824, USA.
Cell. 2023 Aug 3;186(16):3499-3518.e14. doi: 10.1016/j.cell.2023.06.008. Epub 2023 Jul 11.
Chloroplasts are eukaryotic photosynthetic organelles that drive the global carbon cycle. Despite their importance, our understanding of their protein composition, function, and spatial organization remains limited. Here, we determined the localizations of 1,034 candidate chloroplast proteins using fluorescent protein tagging in the model alga Chlamydomonas reinhardtii. The localizations provide insights into the functions of poorly characterized proteins; identify novel components of nucleoids, plastoglobules, and the pyrenoid; and reveal widespread protein targeting to multiple compartments. We discovered and further characterized cellular organizational features, including eleven chloroplast punctate structures, cytosolic crescent structures, and unexpected spatial distributions of enzymes within the chloroplast. We also used machine learning to predict the localizations of other nuclear-encoded Chlamydomonas proteins. The strains and localization atlas developed here will serve as a resource to accelerate studies of chloroplast architecture and functions.
叶绿体是驱动全球碳循环的真核光合细胞器。尽管它们很重要，但我们对其蛋白质组成、功能和空间组织的理解仍然有限。在这里，我们使用荧光蛋白标记在模式藻类衣藻中确定了 1034 种候选叶绿体蛋白的定位。这些定位为研究功能尚不明确的蛋白提供了思路；鉴定了核体、质体小球和淀粉粒的新成分；并揭示了广泛的蛋白质靶向到多个隔室。我们发现并进一步描述了细胞组织特征，包括十一个叶绿体点状结构、胞质新月形结构以及叶绿体中酶的意外空间分布。我们还使用机器学习来预测其他核编码的衣藻蛋白的定位。这里开发的菌株和定位图谱将成为加速叶绿体结构和功能研究的资源。
