A nucleolar AAA-NTPase is required for parasite division.

Area of Science:

• Molecular biology
• Parasitology
• Cell biology

Background:

• Apicomplexa parasites have cell cycles similar to eukaryotes but lack understood control mechanisms.
• Progression through the parasite cell cycle, including the G1 phase before DNA synthesis, is not well understood.

Purpose of the Study:

• To identify and characterize a novel protein involved in regulating the Apicomplexa cell cycle.
• To elucidate the function of this protein in ribosome biogenesis and cell cycle control.

Main Methods:

• Genetic complementation to map the mutation.
• Analysis of a temperature-sensitive cell cycle mutant.
• Investigating protein interactions with snoRNP and R2TP complexes.
• Confirmation of mutation effects via knock-in into the parent genome.

Main Results:

• A novel AAA-ATPase/CDC48 family member, TgNoAP1, was identified as essential for cell cycle progression.
• A specific mutation in TgNoAP1 causes conditional protein instability, leading to G1 phase arrest.
• TgNoAP1 plays a critical role in 28S ribosomal RNA processing.
• TgNoAP1 interacts with snoRNP and R2TP complexes, indicating a role in ribosome biogenesis.

Conclusions:

• TgNoAP1 is a novel cdc48-related chaperone protein with a previously unrecognized role in pre-ribosomal RNA processing.
• TgNoAP1 likely acts as a sensor for protein machinery health during ribosome biogenesis.
• This protein may link ribosome biogenesis status to cell cycle checkpoint controls in Apicomplexa parasites.