Additional remarks phenotype | Mutant/mutation
The mutant lacks expression of NTF2-like domain-containing protein, putative
Protein (function)
Export of mRNA through nuclear pores into the cytoplasm is an essential process in all eukaryotic cells. Mature mRNA is recognized by adaptor proteins such as nuclear poly(A) binding protein 2 (NAB2), yeast RNA annealing protein (YRA1), and three serine/arginine-rich (SR) proteins, including nucleolar protein 3 (NPL3), G-strand binding protein 2 (GBP2) and hypothetical RNA-binding protein (HRB1). The yeast mRNA export receptor, Mex67/Mtr2, recruited by these adaptor proteins interacts with nuclear pore complex proteins to export mRNA into the cytoplasm. Plasmodium possess orthologs of yeast adaptor proteins, but no orthologs of Mex67 and Mtr2. Yeast Mex67 contains a nuclear transport factor 2 (NTF2)-like domain. The NTF2-like domain is necessary for heterodimerization with Mtr2 and for interaction with FG nucleoporins in the nuclear pores. In the PlasmoDB database (www. plasm odb. org/), three proteins containing NTF2-like domains, namely, PBANKA_1019700 (conserved Plasmodium protein), PBANKA_0922900 (mitochondrial import inner membrane translocase subunit TIM44), and PBANKA_1030300 (nuclear transport factor 2), have been annotated. PBANKA_1030300 and PBANKA_0922900 have been reported as being essential to parasite survival during the erythrocytic stage. PBANKA_1030300 binds RanGDP and is associated with protein import to the nucleus from the cytoplasm. PBANKA_0922900 contains a Tim44-like domain, indicating that it localizes to the mitochondria, not to the nucleus of Plasmodium.
Phenotype
Normal development of asexual blood stages. Evidence is presented for reduced production of male en female gametocytes.
Additional information
Aanalysis of a mutant expressing a C-terminal mCherry tagged version of PBANKA_1019700 (RMgm-5525) showed expression in all erythrocytic stages, including trophozoites, schizonts and gametocytes and localization in the cytoplasm of these stages.
To investigate the proteins that interact with the NTF2 domain-containing protein PBANKA_1019700, protein, immunoprecipitation (IP) using anti-mCherry beads was performed and the proteins bound to PBANKA_1019700 were identified through mass spectrometry (MS). Cytoplasmic proteins, including ubiquitin-related proteins (ubiquitin carboxylterminal hydrolase, PBANKA_0210600; ubiquitin-like protein, PBANKA_0823000; HECT-type E3 ubiquitin ligase UT, PBANKA_0802300) and a VPS13 domain-containing protein (PBANKA_1359300) were detected through IP-MS of 1019700::mCherry. However, RNA-binding proteins, such as NAB2 and GBP2, were not detected. In addition, the conserved Plasmodium protein PBANKA_0519900 was detected (see RMgm-5526).
Other mutants |