SRSF12

PF3D7_0503300 (SRSF12) is a serine/arginine-rich splicing factor of Plasmodium falciparum that localizes predominantly to the nucleus of blood stage trophozoites and is also present in the nucleus of gametocytes (PMID:25188378). Its RS-rich domain is a direct in vitro substrate of all four P. falciparum CLK kinases (PfCLK-1 through -4), and this phosphorylation strictly requires the RS domain, positioning SRSF12 as a downstream target of CLK-mediated regulation of pre-mRNA processing (PMID:25188378). Beyond its nuclear localization and CLK-dependent RS-domain phosphorylation, no further mechanistic detail — including RNA targets, splicing activity, or interaction partners — has been characterized for SRSF12 in the available corpus.

1. 2014 Medium

   To establish where SRSF12 could act, its subcellular distribution was resolved, showing a nuclear residence consistent with a role in pre-mRNA processing across asexual and sexual stages.

   Evidence Immunolocalization and subcellular fractionation in P. falciparum blood stage trophozoites and gametocytes

   PMID:25188378

   Open questions at the time

   • No RNA substrates or splicing targets identified
   • No interaction partners or spliceosome association demonstrated
   • Localization not resolved across all life-cycle stages
2. 2014 High

   To connect SRSF12 to an upstream regulatory kinase, its RS-rich domain was tested as a phosphorylation substrate, establishing it as a direct in vitro target of all four PfCLK kinases and defining the RS domain as the required phosphoacceptor region.

   Evidence In vitro kinase assay with recombinant RS-domain-containing PfSRSF12 and recombinant PfCLK-1 through -4, using an RS-domain-lacking control peptide

   PMID:25188378

   Open questions at the time

   • Phosphorylation not demonstrated in vivo in the parasite
   • Functional consequence of RS-domain phosphorylation on splicing activity unknown
   • Which specific residues within the RS domain are phosphorylated is not mapped

• It remains unknown what RNA transcripts SRSF12 processes, whether its CLK-dependent phosphorylation regulates its activity or localization in vivo, and what role it plays in asexual proliferation or gametocyte development.
• No in vivo functional or genetic characterization of SRSF12
• No defined splicing targets or transcriptome-level effect
• No structural model of the SRSF12–CLK interaction