PF3D7_1008700

PF3D7_1008700 encodes P. falciparum beta-tubulin, a 445-amino-acid cytoskeletal protein whose gene contains two introns, is unlinked from the alpha-tubulin locus, and is transcribed as multiple beta-tubulin messages in blood-stage parasites (PMID:2181306). As a microtubule component, it is required for the mitotic divisions of schizogony: purified recombinant parasite beta-tubulin directly binds the dinitroaniline herbicide trifluralin through a site poorly conserved in mammalian (bovine) tubulin, and dinitroaniline treatment blocks schizogony, arrests mitotic division, and produces abnormal microtubular structures (PMID:16406111). This parasite-selective drug-binding site distinguishes it from human tubulin (PMID:16406111). Beta-tubulin also engages the Apicomplexan protein apicortin in vitro, an interaction whose pharmacological disruption impairs blood-stage growth (PMID:33633135).

1. 1990 Medium

   Establishing the gene structure and expression was the necessary first step to define P. falciparum beta-tubulin as a discrete, characterizable cytoskeletal gene distinct from its alpha-tubulin counterpart.

   Evidence Genomic/cDNA library screening, DNA sequencing, and Northern blot of blood-stage parasites

   PMID:2181306

   Open questions at the time

   • The identity and significance of the three distinct transcript sizes were not resolved
   • No protein-level localization or function established at this stage
2. 2005 Medium

   Whether beta-tubulin harbors a parasite-selective drug target was answered by showing direct dinitroaniline binding to parasite but not mammalian tubulin, coupled to a mitotic-arrest phenotype, defining beta-tubulin's role in schizogony and its exploitable pharmacology.

   Evidence Radiolabelled trifluralin binding to purified recombinant parasite tubulin, in vitro growth inhibition, and microscopy of microtubular structures

   PMID:16406111

   Open questions at the time

   • The precise residues forming the dinitroaniline-binding site were not mapped
   • Binding was measured on total recombinant tubulin, not the beta-subunit in isolation with defined stoichiometry
3. 2021 Low

   Whether beta-tubulin participates in a defined protein–protein interaction relevant to survival was addressed by identifying apicortin as an in vitro binding partner whose disruption impairs blood-stage growth.

   Evidence In silico docking with in vitro binding, Tamoxifen-mediated interaction disruption, and blood-stage growth assay

   PMID:33633135

   Open questions at the time

   • No genetic validation of the specific apicortin–beta-tubulin interaction; relies on pharmacology and in vitro binding
   • Tamoxifen's growth effect cannot be attributed solely to this interaction
   • Structural details and cellular localization of the complex not established

• Direct genetic evidence for the essentiality and in vivo function of PF3D7_1008700, and a residue-level structure of its parasite-selective drug-binding site, remain to be established.
• No knockout/conditional-knockdown data for the gene itself
• No high-resolution structure of the dinitroaniline-binding site
• Contribution of individual transcripts and any stage specificity unknown