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Updated: Apr 26, 2026
Author Spotlight: Identifying Compensatory Pathways in Malaria Parasites Containing Hypomorphic Allele of Essential Protein Kinases
Published on: November 22, 2024
Characterization of the small exported Plasmodium falciparum membrane protein SEMP1
Olivier Dietz1, Sebastian Rusch1, Françoise Brand1
1Swiss Tropical and Public Health Institute, Department of Medical Parasitology and Infection Biology, Basel, Switzerland; University of Basel, Basel, Switzerland.
Abstract:
Survival and virulence of the human malaria parasite Plasmodium falciparum during the blood stage of infection critically depend on extensive host cell refurbishments mediated through export of numerous parasite proteins into the host cell. The parasite-derived membranous structures called Maurer's clefts (MC) play an important role in protein trafficking from the parasite to the red blood cell membrane. However, their specific function has yet to be determined. We identified and characterized a new MC membrane protein, termed small exported membrane protein 1 (SEMP1). Upon invasion it is exported into the RBC cytosol where it inserts into the MCs before it is partly translocated to the RBC membrane. Using conventional and conditional loss-of-function approaches we showed that SEMP1 is not essential for parasite survival, gametocytogenesis, or PfEMP1 export under culture conditions. Co-IP experiments identified several potential interaction partners, including REX1 and other membrane-associated proteins that were confirmed to co-localize with SEMP1 at MCs. Transcriptome analysis further showed that expression of a number of exported parasite proteins was up-regulated in SEMP1-depleted parasites. By using Co-IP and transcriptome analysis for functional characterization of an exported parasite protein we provide a new starting point for further detailed dissection and characterisation of MC-associated protein complexes.
Insights
Researchers identified small exported membrane protein 1 (SEMP1), a novel protein in malaria parasites Plasmodium falciparum. SEMP1 is not essential for parasite survival but influences the expression of other exported proteins.
Area of Science:
- Malariology
- Molecular Parasitology
- Cell Biology
Background:
- The malaria parasite Plasmodium falciparum extensively modifies host red blood cells (RBCs) during blood-stage infection.
- Maurer's clefts (MCs) are parasite-derived structures crucial for exporting proteins to the RBC membrane, but their precise functions remain unclear.
Purpose of the Study:
- To identify and characterize novel proteins associated with Maurer's clefts.
- To investigate the function of a newly identified MC protein, small exported membrane protein 1 (SEMP1), in Plasmodium falciparum.
Main Methods:
- Identification and characterization of SEMP1.
- Loss-of-function studies using conventional and conditional approaches.
- Co-immunoprecipitation (Co-IP) to identify interaction partners.
- Transcriptome analysis to assess gene expression changes.
Main Results:
- SEMP1 is exported to the RBC cytosol, inserts into MCs, and partially translocates to the RBC membrane.
- SEMP1 is not essential for parasite survival, gametocytogenesis, or PfEMP1 export in vitro.
- SEMP1 interacts with other MC-associated proteins, including REX1.
- Depletion of SEMP1 leads to upregulation of several other exported parasite proteins.
Conclusions:
- SEMP1 is a novel Maurer's cleft protein involved in protein trafficking within the infected RBC.
- While not essential for basic survival, SEMP1 plays a role in regulating the expression of other exported proteins.
- This study provides a foundation for further research into MC-associated protein complexes and their roles in malaria pathogenesis.
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