SCYL2 Genes Are Involved in Clathrin-Mediated Vesicle Trafficking and Essential for Plant Growth

Abstract

Protein transport between organelles is an essential process in all eukaryotic cells and is mediated by the regulation of processes such as vesicle formation, transport, docking, and fusion. In animals, SCY1-LIKE2 (SCYL2) binds to clathrin and has been shown to play roles in trans-Golgi network-mediated clathrin-coated vesicle trafficking. Here, we demonstrate that SCYL2A and SCYL2B, which are Arabidopsis (Arabidopsis thaliana) homologs of animal SCYL2, are vital for plant cell growth and root hair development. Studies of the SCYL2 isoforms using multiple single or double loss-of-function alleles show that SCYL2B is involved in root hair development and that SCYL2A and SCYL2B are essential for plant growth and development and act redundantly in those processes. Quantitative reverse transcription-polymerase chain reaction and a b-glucuronidase-aided promoter assay show that SCYL2A and SCYL2B are differentially expressed in various tissues. We also show that SCYL2 proteins localize to the Golgi, trans-Golgi network, and prevacuolar compartment and colocalize with Clathrin Heavy Chain1 (CHC1). Furthermore, bimolecular fluorescence complementation and coimmunoprecipitation data show that SCYL2B interacts with CHC1 and two Soluble NSF Attachment Protein Receptors (SNAREs): Vesicle Transport through t-SNARE Interaction11 (VTI11) and VTI12. Finally, we present evidence that the root hair tip localization of Cellulose Synthase-Like D3 is dependent on SCYL2B. These findings suggest the role of SCYL2 genes in plant cell developmental processes via clathrin-mediated vesicle membrane trafficking.

At the intersection of exocytosis and endocytosis in plants

“…Polarized cell expansion in plant tip‐growing cells, such as root hairs and pollen tubes, involves massive exocytic and endocytic vesicle trafficking (Grebnev et al ., ; Jung et al ., ). Membrane trafficking during tip growth is well characterized in pollen tubes.…”

Genome-wide identification, evolution, and expression of the SNARE gene family in wheat resistance to powdery mildew

“…In Arabidopsis , severe male gametophytic defects occur only when syp123 , syp125 , and syp131 were simultaneously mutated ( Slane et al, 2017 ). Arabidopsis SCYL2B and CHC1 undergo vesicle transport through VTI11 or VTI12 for plant growth ( Jung et al, 2017 ). On the other hand, homoeologous genes may also play different roles.…”

Complex roles of Rabs and SNAREs in the secretory pathway and plant development: a never‐ending story

“…These results supported the implication of the tethering factor TNO1 in vesicle fusion at the TGN (Yang et al ., 2019). Finally, SCYL2A/B are clathrin‐binding proteins which interact with the Qb‐SNAREs AtVTI11 and AtVTI12, and CHC1, supporting the notion that SCYL2A/B proteins are involved in clathrin‐mediated vesicle trafficking (Jung et al ., 2017). Root hair tip‐localised proteins such as ROP2, RHD2, RabA4b, SYP123 and CSLD3, are critical for proper root hair tip growth, but only CSLD3 was mislocalised in the root hairs of scyl2b mutants, supporting the conclusion that SCYL2B mediates to some extent the tip localisation of CSLD3 (Cellulose Synthase‐Like protein D3) in root hairs.…”

“…Root hair tip‐localised proteins such as ROP2, RHD2, RabA4b, SYP123 and CSLD3, are critical for proper root hair tip growth, but only CSLD3 was mislocalised in the root hairs of scyl2b mutants, supporting the conclusion that SCYL2B mediates to some extent the tip localisation of CSLD3 (Cellulose Synthase‐Like protein D3) in root hairs. Therefore, SCYL2B may act as a component of clathrin‐mediated vesicle membrane trafficking that regulates secretory processes mediated by TGN and PVC in the process of root hair tip growth (Jung et al ., 2017).…”