Identification of GBP2- and NAB2-interacting proteins in malaria parasites

ABSTRACT: The quality control and export of mRNA by RNA-binding proteins are necessary for the survival of malaria parasites, which have complex life cycles. Malarial nuclear poly(A) binding protein 2 (NAB2), ALWAYS EARLY (ALY) and serine/arginine-rich (SR) proteins, such as nucleolar protein 3 (NPL3), G-strand binding protein 2 (GBP2) and SR1, are involved in nuclear mRNA export in malaria parasites. However, their functions and cellular localization are not fully understood. In this study, we found that NAB2 and SR1, but not ALY, NPL3 or GBP2, played essential roles in the asexual development of malaria parasites, while GBP2 was involved in gametocyte production. Moreover, GBP2 localized to both the nucleus and cytoplasm of malaria parasites and interacted with the proteins ALBA4, DOZI and CITH, which play roles in translational repression. Our findings suggest that malarial GBP2 may be involved in the recruitment of ALBA4, DOZI and CITH. Immunoprecipitation coupled to mass spectrometry (IP-MS) revealed that PHAX domain-containing protein, an adaptor protein for exportin-1, also interacted with GBP2, suggesting that mRNA export occurs via the PHAX domain-containing protein pathway in malaria parasites. Fluorescence live cell imaging revealed that malarial NAB2 localized at the nuclear periphery and co-localized with NUP205. Moreover, using IP-MS, we found that malarial NAB2 interacted with transportin. RNA immunoprecipitation coupled to RNA sequencing revealed that malarial NAB2 bound directly to 143 mRNAs, including those encoding 40S and 60S ribosomal proteins. This indicates that malarial NAB2 is involved in general mRNA assembly and is shuttled between the nucleus and cytoplasm. Our findings suggest that unique mRNA export and post-transcriptional gene regulation mediated by RNA-binding proteins occur in malaria parasites.

INSTRUMENT(S): LTQ Orbitrap Velos

ORGANISM(S): Plasmodium Berghei Anka

SUBMITTER: Mamoru Niikura  

LAB HEAD: Mamoru Niikura

PROVIDER: PXD027302 | Pride | 2021-11-03

REPOSITORIES: Pride