Authors

N E Padilla-Mejia¹; E R Butterfield¹; L Koreny⁴; S O Obado³; S R Scutts²; B T Chait³; M P Rout³; M C Field¹;  ¹ Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee;  ² Department of Pathology, University of Cambridge;  ³ The Rockefeller University, United States;  ⁴ University of Cambridge, Department of Biochemistry

Discussion

The nucleus is contained by the nuclear envelope (NE) which associates with multi-protein complexes, these function in structural support (lamina), bidirectional transport of RNA and proteins (nuclear pore complex), nuclear positioning (LINC complex) and signal transduction in higher eukaryotes. The lamina is associated with chromosomal and heterochromatin organisation and transcription and regulation of replication. Proteins with similar functions have been identified in organisms across different evolutionary supergroups. In Trypanosoma brucei two lamina proteins have been identified, NUP-1 and NUP-2, involved in the maintenance of the nuclear architecture, organization of the heterochromatin, chromosome positioning and variant surface glycoprotein switching regulation. To further characterise lamina function and identify possible interacting partners in T. brucei, we used co-immunoprecipitation, imaging, overexpression analysis and comparative genomics. We conclude NUP-1 has three domains with indications both the N and C-terminus act as nucleation/polymerisation sites. We have also identified proteins which interact with NUPs which we termed NAPs for NUP associated proteins. These proteins are predicted to be localised to the nucleus and contain domains related to nuclear activities. Overall, these advances are leading us to define the manner in which the NE is structured, how it participates within the cell cycle and how its components interact.