Identification of TbPBN1 in Trypanosoma brucei reveals a conserved heterodimeric architecture for glycosylphosphatidylinositol-mannosyltransferase I.

Cowton, Andrew; Bütikofer, Peter; Häner, Robert; Menon, Anant K (2022). Identification of TbPBN1 in Trypanosoma brucei reveals a conserved heterodimeric architecture for glycosylphosphatidylinositol-mannosyltransferase I. Molecular microbiology, 117(2), pp. 450-461. Wiley 10.1111/mmi.14859

[img]
Preview
Text
Molecular_Microbiology_-_2021_-_Cowton_-_Identification_of_TbPBN1_in_Trypanosoma_brucei_reveals_a_conserved_heterodimeric.pdf - Published Version
Available under License Creative Commons: Attribution (CC-BY).

Download (1MB) | Preview

Glycosylphosphatidylinositol (GPI)-anchored proteins are found in all eukaryotes and are especially abundant on the surface of protozoan parasites such as Trypanosoma brucei. GPI-mannosyltransferase I (GPI-MT-I) catalyses the addition of the first of three mannoses that make up the glycan core of GPI. Mammalian and yeast GPI-MT-I consist of two essential subunits, the catalytic subunit Gpi14/Pig-M and the accessory subunit Pbn1/Pig-X (mammals/yeast). T. brucei GPI-MT-I has been highlighted as a potential anti-trypanosome drug target but has not been fully characterised. Here, we show that T. brucei GPI-MT-I also has two subunits, TbGPI14 and TbPBN1. Using TbGPI14 deletion, and TbPBN1 RNAi-mediated depletion, we show that both proteins are essential for the mannosyltransferase activity needed for GPI synthesis and surface expression of GPI-anchored proteins. In addition, using native PAGE and co-immunoprecipitation analyses, we demonstrate that TbGPI14 and TbPBN1 interact to form a higher-order complex. Finally, we show that yeast Gpi14 does not restore GPI-MT-I function in TbGPI14 knockout trypanosomes, consistent with previously demonstrated species specificity within GPI-MT-I subunit associations. The identification of an essential trypanosome GPI-MT-I subcomponent indicates wide conservation of the heterodimeric architecture unusual for a glycosyltransferase, leaving open the question of the role of the non-catalytic TbPBN1 subunit in GPI-MT-I function.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Department of Chemistry, Biochemistry and Pharmaceutical Sciences (DCBP)
04 Faculty of Medicine > Pre-clinic Human Medicine > Institute of Biochemistry and Molecular Medicine

UniBE Contributor:

Cowton, Andrew Robert; Bütikofer, Peter and Häner, Robert

Subjects:

500 Science > 570 Life sciences; biology
500 Science > 540 Chemistry
600 Technology > 610 Medicine & health

ISSN:

1365-2958

Publisher:

Wiley

Language:

English

Submitter:

Barbara Franziska Järmann-Bangerter

Date Deposited:

20 Jan 2022 08:13

Last Modified:

16 Feb 2022 00:13

Publisher DOI:

10.1111/mmi.14859

PubMed ID:

34875117

Uncontrolled Keywords:

Endoplasmic reticulum (ER) Trypanosoma brucei glycosylphosphatidylinositol (GPI) glycosyltransferase mannosyltransferase

BORIS DOI:

10.48350/163145

URI:

https://boris.unibe.ch/id/eprint/163145

Actions (login required)

Edit item Edit item
Provide Feedback