Translation initiation factors GleIF4E2 and GleIF4A can interact directly with the components of the pre-initiation complex to facilitate translation initiation in Giardia lamblia

Publication date: Available online 20 January 2020Source: Molecular and Biochemical ParasitologyAuthor(s): Adebanjo Najeem Adedoja, Timothy McMahan, John Patrick Neal, Siddhartha Hamal Dhakal, Seetharama Jois, Daniel Romo, Ken Hull, Srinivas GarlapatiAbstractTranslation initiation factor eIF4F is essential for cap-dependent translation initiation in eukaryotes. eIF4F is a trimeric complex consisting of a scaffold protein eIF4G, cap-binding protein eIF4E and DEAD-box RNA helicase eIF4A. eIF4F binds to the 5’ cap structure of the mRNA through eIF4E and facilitates the binding of the preinitiation complex (PIC) via protein-protein interactions of eIF4G with eIF3 in mammals or with eIF5 in yeast. Initiation factor eIF4A is known to unwind the secondary structures of the 5’UTRs encountered by the PIC during its initial binding to the mRNA and while scanning for the initiation codon. In Giardia, homologs for eIF4E (GleIF4E2) and eIF4A (GleIF4A) have been identified but not for eIF4G. To address how PIC is recruited to the 5’ end of mRNA in the absence of eIF4G homolog, we have used yeast two-hybrid assays to identify potential interactions of GleIF4E2 with the components of the PIC. The results show that GleIF4E2 can interact with the β subunit of the initiation factor GleIF2, a component of the PIC. ZDOCK modeling of the GleIF4E2-GleIF2β complex revealed that the dorsal side of GleIF4E2 is likely involved in binding to GleIF2β, which mimics the interaction of mammalian eI...
Source: Molecular and Biochemical Parasitology - Category: Parasitology Source Type: research