Research
| Title： | Structural and functional regulation of Chlamydomonas lysosome-related organelles during environmental changes |
|---|---|
| First author： | Long, Huan; Fang, Jinhua; Ye, Lian; Zhang, Baolong; Hui, Colleen; Deng, Xuan; Merchant, Sabeeha S.; Huang, Kaiyao |
| Journal： | PLANT PHYSIOLOGY |
| Years： | 2023 |
| DOI： | 10.1093/plphys/kiad189 |
| Abstract： | Lysosome-related organelles (LROs) are a class of heterogeneous organelles conserved in eukaryotes that primarily play a role in storage and secretion. An important function of LROs is to mediate metal homeostasis. Chlamydomonas reinhardtii is a model organism for studying metal ion metabolism; however, structural and functional analyses of LROs in C. reinhardtii are insufficient. Here, we optimized a method for purifying these organelles from 2 populations of cells: stationary phase or overloaded with iron. The morphology, elemental content, and lysosomal activities differed between the 2 preparations, even though both have phosphorus and metal ion storage functions. LROs in stationary phase cells had multiple non-membrane-bound polyphosphate granules to store phosphorus. Those in iron-overloaded cells were similar to acidocalcisomes (ACs), which have a boundary membrane and contain 1 or 2 large polyphosphate granules to store more phosphorus. We established a method for quantifying the capacity of LROs to sequester individual trace metals. Based on a comparative proteomic analysis of these 2 types of LROs, we present a comprehensive AC proteome and identified 113 putative AC proteins. The methods and protein inventories provide a framework for studying the biogenesis and modification of LROs and the mechanisms by which they participate in regulating metal ion metabolism. The structure and function of Chlamydomonas lysosome-related organelles are regulated in response to environmental changes. |
