TY  - JOUR
A1  - Broster Reix, Christine E.
A1  - Florimond, Célia
A1  - Cayrel, Anne
A1  - Mailhé, Amélie
A1  - Agnero-Rigot, Corentin
A1  - Landrein, Nicolas
A1  - Dacheux, Denis
A1  - Havlicek, Katharina
A1  - Bonhivers, Mélanie
A1  - Morriswood, Brooke
A1  - Robinson, Derrick R.
T1  - Bhalin, an essential cytoskeleton-associated protein of Trypanosoma brucei linking TbBILBO1 of the flagellar pocket collar with the hook complex
JF  - Microorganisms
N2  - Background: In most trypanosomes, endo and exocytosis only occur at a unique organelle called the flagellar pocket (FP) and the flagellum exits the cell via the FP. Investigations of essential cytoskeleton-associated structures located at this site have revealed a number of essential proteins. The protein TbBILBO1 is located at the neck of the FP in a structure called the flagellar pocket collar (FPC) and is essential for biogenesis of the FPC and parasite survival. TbMORN1 is a protein that is present on a closely linked structure called the hook complex (HC) and is located anterior to and overlapping the collar. TbMORN1 is essential in the bloodstream form of T. brucei. We now describe the location and function of BHALIN, an essential, new FPC-HC protein. Methodology/Principal Findings: Here, we show that a newly characterised protein, BHALIN (BILBO1 Hook Associated LINker protein), is localised to both the FPC and HC and has a TbBILBO1 binding domain, which was confirmed in vitro. Knockdown of BHALIN by RNAi in the bloodstream form parasites led to cell death, indicating an essential role in cell viability. Conclusions/Significance: Our results demonstrate the essential role of a newly characterised hook complex protein, BHALIN, that influences flagellar pocket organisation and function in bloodstream form T. brucei parasites.
KW  - trypanosoma
KW  - flagellar pocket
KW  - hook complex
KW  - endocytosis
KW  - cytoskeleton
KW  - protozoan
KW  - flagellar pocket collar
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-250301
SN  - 2076-2607
VL  - 9
IS  - 11
ER  - 
TY  - JOUR
A1  - Sajko, Sara
A1  - Grishkovskaya, Irina
A1  - Kostan, Julius
A1  - Graewert, Melissa
A1  - Setiawan, Kim
A1  - Trübestein, Linda
A1  - Niedermüller, Korbinian
A1  - Gehin, Charlotte
A1  - Sponga, Antonio
A1  - Puchinger, Martin
A1  - Gavin, Anne-Claude
A1  - Leonard, Thomas A.
A1  - Svergun, Dimitri I.
A1  - Smith, Terry K.
A1  - Morriswood, Brooke
A1  - Djinovic-Carugo, Kristina
T1  - Structures of three MORN repeat proteins and a re-evaluation of the proposed lipid-binding properties of MORN repeats
JF  - PLoS One
N2  - MORN (Membrane Occupation and Recognition Nexus) repeat proteins have a wide taxonomic distribution, being found in both prokaryotes and eukaryotes. Despite this ubiquity, they remain poorly characterised at both a structural and a functional level compared to other common repeats. In functional terms, they are often assumed to be lipid-binding modules that mediate membrane targeting. We addressed this putative activity by focusing on a protein composed solely of MORN repeats-Trypanosoma brucei MORN1. Surprisingly, no evidence for binding to membranes or lipid vesicles by TbMORN1 could be obtained either in vivo or in vitro. Conversely, TbMORN1 did interact with individual phospholipids. High- and low-resolution structures of the MORN1 protein from Trypanosoma brucei and homologous proteins from the parasites Toxoplasma gondii and Plasmodium falciparum were obtained using a combination of macromolecular crystallography, small-angle X-ray scattering, and electron microscopy. This enabled a first structure-based definition of the MORN repeat itself. Furthermore, all three structures dimerised via their C-termini in an antiparallel configuration. The dimers could form extended or V-shaped quaternary structures depending on the presence of specific interface residues. This work provides a new perspective on MORN repeats, showing that they are protein-protein interaction modules capable of mediating both dimerisation and oligomerisation.
KW  - recognition nexus domain
KW  - trypanosoma brucei
KW  - blood stream
KW  - phosphatidylserine transport
KW  - biological macromolecules
KW  - membrane occupation
KW  - solution scattering
KW  - molecular cloning
KW  - flagellar pocket
KW  - endocytosis
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-231261
VL  - 15
IS  - 23
ER  -