The TPLATE complex mediates membrane bending during plant clathrin–mediated endocytosis

Abstract

Clathrin-mediated endocytosis is the major route of entry of cargos into cells and thus underpins many physiological processes. During endocytosis, an area of flat membrane is remodeled by proteins to create a spherical vesicle against intracellular forces. The protein machinery which mediates this membrane bending in plants is unknown. However, it is known that plant endocytosis is actin independent, thus indicating that plants utilize a unique mechanism to mediate membrane bending against high-turgor pressure compared to other model systems. Here, we investigate the TPLATE complex, a plant-specific endocytosis protein complex. It has been thought to function as a classical adaptor functioning underneath the clathrin coat. However, by using biochemical and advanced live microscopy approaches, we found that TPLATE is peripherally associated with clathrin-coated vesicles and localizes at the rim of endocytosis events. As this localization is more fitting to the protein machinery involved in membrane bending during endocytosis, we examined cells in which the TPLATE complex was disrupted and found that the clathrin structures present as flat patches. This suggests a requirement of the TPLATE complex for membrane bending during plant clathrin–mediated endocytosis. Next, we used in vitro biophysical assays to confirm that the TPLATE complex possesses protein domains with intrinsic membrane remodeling activity. These results redefine the role of the TPLATE complex and implicate it as a key component of the evolutionarily distinct plant endocytosis mechanism, which mediates endocytic membrane bending against the high-turgor pressure in plant cells.

Compromised osteogenic effect of exosomes internalized by senescent bone marrow stem cells via endocytoses involving clathrin, macropinocytosis and caveolae

“…As non-senescent cellular environment of BMSCs internalized exosomes exclusively via clathrin-mediated endocytosis, senescent BMSCs required additional involvement of macropinocytosis and caveolae-mediated endocytosis to mediate the internalization of exosomes. Clathrin-mediated endocytosis was reported as the common endocytic channel that play an important role in the positive regulation of many intracellular signaling cascades ( Hoban et al, 2020 ; Johnson et al, 2021 ). Caveolae was the most commonly reported non-clathrin coated plasma membrane buds with flask-shaped invaginations that existed on the surface of many mammalian cell types including smooth muscle, type I pneumocytes, fibroblasts, adipocytes, and endothelial cells ( Nanbo et al, 2013 ).…”

Local endocytosis of sucrose transporter 2 in duckweed reveals the role of sucrose transporter 2 in guard cells

“…Endocytosis, one of the basic cellular processes, determines the fate of many PM proteins and affects a large number of signal pathways ( Mao et al., 2021 ), the cells’ glucose uptaking ( Seaman, 2012 ), and the maintenance of intracellular metal ions stability ( Steinberg et al., 2013 ; Curnock and Cullen, 2020 ). In the past few decades, endocytosis of PM proteins has always been a research hotspot ( Johnson et al., 2021 ), such as StSUT1 accumulates in lipid raft-like microdomains under oxidizing conditions ( Krugel et al., 2008 ) and StSUT1 endocytosis and recycling at the plasma membrane ( Liesche et al., 2008 ). In addition, sucrose transporters from peach trees are shown to undergo substrate-induced endocytosis ( Zanon et al., 2015 ).…”

“…Endocytosis, the major route of PM (plasma membrane) proteins to enter cells, is an evolutionarily conserved eukaryotic pathway that internalizes extracellular substances and PM components through vesicles ( Johnson et al., 2021 ; Su et al., 2021 ). Endocytosis plays a central role in many developmental and physiological processes in plants by regulating the abundance and activity of PM proteins ( Wang et al., 2021 ; Wang et al., 2022 ), especially during the polar growth of cells ( Li et al., 2018 ) or under hyperosmotic stress ( Martinière et al., 2019 ).…”

An Update on Coat Protein Complexes for Vesicle Formation in Plant Post-Golgi Trafficking

“…The molecular architectures of TPC are recently solved, revealing high similarities between TPC and the AP2-clathrin complex at the structural level ( Yperman et al, 2021 ). In another study, a remarkable membrane-bending activity of TPC subunits during CCV formation was observed, which indicates a distinct mechanism of TPC in mediating plant endocytosis ( Johnson et al, 2021 ). It would be interesting for future studies to further investigate how different signals are perceived by TPC- and the AP20-clathrin-mediated pathways.…”