Nagel, M.-K. | bioRxiv Science

bioRxiv2023

Role of Dynamin-Related Proteins 2 and SH3P2 in Clathrin-Mediated Endocytosis in Plants

Clathrin-mediated endocytosis (CME) is vital for the regulation of plant growth and development by controlling plasma membrane protein composition and cargo uptake. CME relies on the precise recruitment of regulators for vesicle maturation and release. Homologues of components of mammalian vesicle scission are strong candidates to be part of the scissin machinery in plants, but the precise roles of these proteins in this process is not fully understood. Here, we characterised the roles of Plant Dynamin-Related Proteins 2 (DRP2s) and SH3-domain containing protein 2 (SH3P2), the plant homologue to Dynamins recruiters, like Endophilin and Amphiphysin, in the CME by combining high-resolution imaging of endocytic events in vivo and characterisation of the purified proteins in vitro. Although DRP2s and SH3P2 arrive similarly late during CME and physically interact, genetic analysis of the Dsh3p1,2,3 triple-mutant and complementation assays with non-SH3P2-interacting DRP2 variants suggests that SH3P2 does not directly recruit DRP2s to the site of endocytosis. These observations imply that despite the presence of many well-conserved endocytic components, plants have acquired a distinct mechanism for CME. One Sentence SummaryIn contrast to predictions based on mammalian systems, plant Dynamin-related proteins 2 are recruited to the site of Clathrin-mediated endocytosis independently of BAR-SH3 proteins.

plant biology↗

bioRxiv2018

Tissue morphogenesis mediated by the Arabidopsis receptor kinase STRUBBELIG involves a clathrin-dependent process

HighlightThe Arabidopsis receptor kinase STRUBBELIG is internalized by clathrin-mediated endocytosis and affects clathrin-dependent processes in a tissue-dependent manner.\n\nAbstractSignaling mediated by cell surface receptor kinases is central to the coordination of growth patterns during organogenesis. Receptor kinase signaling is in part controlled through endocytosis and subcellular distribution of the respective receptor kinase. For the majority of plant cell surface receptors the underlying trafficking mechanisms are not characterized. In Arabidopsis, tissue morphogenesis relies on the atypical receptor kinase STRUBBELIG (SUB). Here, we approach the endocytic mechanism of SUB. Our data reveal that a functional SUB:EGFP fusion is ubiquitinated in vivo. We further show that plasma membrane-bound SUB:EGFP becomes internalized in a clathrin-dependent fashion. We also find that SUB:EGFP associates with the trans-Golgi network and accumulates in multivesicular bodies and the vacuole. Coimmunoprecipitation experiments reveal that SUB:EGFP and clathrin are present within the same protein complex. Our genetic analysis shows that SUB and CLATHRIN HEAVY CHAIN 2 promote root hair patterning. By contrast, SUB behaves as a negative regulator of a clathrin-dependent process during floral development. Taken together, the data indicate that SUB undergoes clathrin-mediated endocytosis, that this process does not dependent on stimulation of SUB signaling by an exogenous agent, and that SUB genetically interacts with clathrin-dependent pathways in a tissue-specific manner.

plant biology↗