Date of Award
1-20-2025
Degree Type
Thesis
Degree Name
Master of Science (MS)
Department
Biology
First Advisor
Stefan Kanzok
Abstract
In eukaryotes, microtubules (MTs) are regulated by microtubule-associated proteins (MAP), only a few of which have been characterized in the malaria parasite to date. Here we present the functional characterization of STOP axonemal protein 1 (SAXO1) of the rodent parasite Plasmodium berghei. The protein exhibits high sequence and organizational conservation to the subpellicular microtubule protein 1 (SPM1) of the apicomplexan parasite Toxoplasma gondii and SAXO1 of Trypanosoma brucei. SAXO1 proteins are conserved in most eukaryotes where they form a protein family. We refer to this protein as PbSPM1. It is a 38 kD protein that is organized into an N-terminal projectile domain followed by a tubulin-binding domain, which consists of 6 identical repeats, and a C-terminal tail domain. Using a human cell line, U2OS, we demonstrate that PbSPM1 associates with microtubules via its microtubule-binding domain. We generated a P. berghei SPM1 KO strain using CRISPR/Cas 9. Our results show that PbSPM1 is not essential for asexual parasite development. We did however observe mature schizonts with unorganized dispersed merozoites. Immunofluorescence (IFA) revealed that the microtubules in SPM1-KO parasites did not efficiently polymerize and did not form discernable microtubule organization centers (MTOC), which was in contrast to the wild-type parasite. These results indicate that SPM1 stabilizes microtubules in the parasite. It was recently reported that SAXO1 localizes to the lumen of microtubules and forms an internal lattice that associates longitudinally with microtubule filaments. Our data support the hypothesis that a main function of PbSPM11 is the stabilization of microtubules.
Recommended Citation
Widuch, Manuel Joseph, "Plasmodium berghei Subpellicular Microtubule Protein-1 (PbSPM-1) is a Microtubule Stabilizing Protein That Affects Schizont Development" (2025). Master's Theses. 4559.
https://ecommons.luc.edu/luc_theses/4559
