Biology subjects

Niemeyer, P. W.

Publications and source records attributed to Niemeyer, P. W..

2 recordsLinked to original sources

bioRxiv2022

SLDP and LIPA mediate lipid droplet-plasma membrane tethering in Arabidopsis thaliana

Membrane contact sites (MCS) are inter-organellar connections that allow for the direct exchange of molecules, such as lipids or Ca2+ between organelles, but can also serve to tether organelles at specific locations within cells. Here we identified and characterised three proteins that form a lipid droplet (LD)-plasma membrane (PM) tethering complex in plant cells, namely LD-localised SEED LD PROTEIN (SLDP) 1 and 2 and PM-localised LD-PLASMA MEMBRANE ADAPTOR (LIPA). Using proteomics and different protein-protein interaction assays, we show that both SLDPs associate with LIPA. Disruption of either SLDP1 and 2 expression, or that of LIPA, leads to an aberrant clustering of LDs in Arabidopsis seedlings. Ectopic co-expression of one of the SLDPs with LIPA on the other hand is sufficient to reconstitute LD-PM tethering in Nicotiana tabacum pollen tubes, a cell type characterised by dynamically moving LDs in the cytosolic streaming. Further, confocal laser scanning microscopy revealed both SLDP2.1 and LIPA to be enriched at LD-PM contact sites in seedlings. These and other results suggest that SLDP and LIPA interact to form a tethering complex that anchors a subset of LDs to the PM during post-germinative seedling growth in Arabidopsis thaliana. One-sentence summarySEED LIPID DROPLET PROTEIN1 and 2 and LIPID DROPLET PLASMA MEMBRANE ADAPTOR tether lipid droplets to the plasma membrane in seedlings of Arabidopsis thaliana.

plant biology↗

bioRxiv2020

Co-option of a seed-like proteome by oil-rich tubers

Co-option is an important aspect of evolution that can occur on several levels. Genes, whose function was molded by selection in the evolutionary past, are readily observed to serve a new function when acting in a different context in an extant system. Whole organs can be co-opted for new roles as well. For example, roots that evolved from shoot-like axes. Finally a framework of genes and its coded proteins can be co-opted to serve a similar molecular function but in a completely different organ, drastically changing its properties. Here, we describe such an example, where a set of proteins important for desiccation tolerance and oil accumulation in seeds of most angiosperms was co-opted in the tubers of yellow nutsedge (Cyperus esculentus). These tubers are not only desiccation tolerant but also store a large amount of lipids--especially TAG, similar to seeds. We generated nanoLC-MS/MS-based proteomes in five replicates of four stages of tuber development and compared them to the proteomes of roots and leaves, yielding 2257 distinct protein groups. Our data reveal a striking upregulation of hallmark proteins of seeds in the tubers. A deeper comparison to a previously published proteome of Arabidopsis seeds and seedlings indicate that indeed a seed-like proteome was co-opted. This was further supported by an analysis of the proteome of a lipid-droplet enriched fraction of yellow nutsedge, which also displayed seed-like characteristics.

evolutionary biology↗