Just three papers this week in the UK Arabidopsis Research Roundup. Firstly Professor Anna Amtmann provides an audio description of her groups characterisation of the binding partners of the Histone Deacetylase Complex1 protein. Secondly Dr Carine De Marcos Lousa leads a study that investigates a set of plant-specific proteins involved in the cellular secretory pathway. Finally Dr Paul Devlin is a contributor to a study that characterises the role of a nucleoporin protein in the shade avoidance response.
Perrella G, Carr C, Asensi-Fabado MA, Donald NA, Páldi K, Hannah MA, Amtmann A (2016) The Histone Deacetylase Complex (HDC) 1 protein of Arabidopsis thaliana has the capacity to interact with multiple proteins including histone 3-binding proteins and histone 1 variants. Plant Physiol. http://dx.doi.org/10.1104/pp.15.01760 Open Access
Anna Amtmann (Glasgow) leads this European collaboration that investigates the binding capability of the Histone Deacetylase Complex (HDC) 1 protein, which has been previously shown to regulate multiple growth phenotypes due to its interaction with histone deacetylases. HDC1 proteins are ubiquitously present throughout plant tissues yet their secondary structure offers little clue to their specific binding interactions. Therefore this attempt to dissect the interaction spectrum of HDC1 and discovered that the protein interacts with different histone3 (H3) binding proteins but not H3 itself. Interestingly HDC1 could also interact with different variants of the H1 histone linker protein. The authors show that the ancestral core of HDC1 had a narrower range of interactions indicating that over evolutionary time the protein had developed more promiscuous binding. However even the conserved portion of the protein is able to interact with H3-associated proteins and H1, indicating that HDC1 played an important role in the establishment of interactions between histones and modifying enzymes.
Professor Amtmann kindly provides a short audio description of this paper. Apologies for the variation in sound quality and volume!
de Marcos Lousa C, Soubeyrand E, Bolognese P, Wattelet-Boyer V, Bouyssou G, Marais C, Boutté Y, Filippini F, Moreau P (2016) Subcellular localization and trafficking of phytolongins (non-SNARE longins) in the plant secretory pathway J Exp Bot. http://dx.doi.org/0.1093/jxb/erw094 Open Access
Carine De Marcos Lousa (Leeds Beckett) is the lead author in the UK-French-Italian study that investigates the activity of plant specific R-SNARE proteins, called longins. SNARE proteins are critical for the membrane fusion events that occur during intracellular transport. A new four-member family of longins called ‘phytolongins’ (Phyl) that lack a typical SNARE domain have recently been discovered. These ubiquituosly expressed proteins are distributed throughout the secretory pathway with different members localised at ER, Golgi apparatus or post-Golgi compartments. Furthermore the export of the Phyl1.1 protein from the ER is dependent on a Y48F49 motif as well as the activity of at least three accessory proteins. This manuscript is the first characterisation of Phyl subcellular localisation and adds to our knowledge of specific mechanisms involved in the plant secretory pathway.
Gallemí M, Galstyan A, Paulišić S, Then C, Ferrández-Ayela A, Lorenzo-Orts L, Roig-Villanova I, Wang X, Micol JL, Ponce MR, Devlin PF, Martínez-García JF (2016) DRACULA2, a dynamic nucleoporin with a role in the regulation of the shade avoidance syndrome in Arabidopsis. Development. http://dx.doi.org/10.1242/dev.130211
This Spanish-led study includes Dr Paul Devlin (RHUL) and introduces a new gene that is involved in the shade-avoidance-response in Arabidopsis. The DRACULA2 gene is a homolog of the metazoan nucleoporin NUP98, which is a component of the nuclear pore complex (NPC). The authors find that other members of the NPC are also involved in the control of hypocotyl elongation in response to proximity of other plants. This is likely due to nuclear transport-dependent processes. However the authors suggest that DRA2 also has a transport-independent role that is related to its physical association with the NPC. This demonstrates that nucleoporins play an important role in plant signaling, although assigning specificity to their activity remains difficult given their general role in nucleocytoplasmic transport.