진학프로석·박사 채용 접수 플랫폼

KEY WORDS: Dicer ribonucleases, RNase III enzymes, helicases, ATP-hydrolyzing proteins, protein-nucleic acid interactions, regulatory RNAs

Principal Investigator: Assoc. Prof. Anna Kurzynska-Kokorniak, PhD, DSc

Research topic: characterization and biological significance of the ATPase activity of human ribonuclease Dicer

I. Project description

Ribonucleases Dicer are multidomain proteins, widely known for their important role in the biogenesis of small regulatory RNAs: microRNAs and small interfering RNAs. This project focuses on the helicase domain of human ribonuclease Dicer (hDicer).

The helicase domain of hDicer contains conserved ATPase motifs. However, it is suggested that the ancestors of hDicer exhibited reduced affinity for ATP, resulting in the loss of its hydrolysis ability - unlike plant or some insect Dicer proteins. Therefore, it remains a mystery why hDicer has retained these conserved ATPase motifs? Importantly, results from our recent studies indicate that the helicase domain of hDicer is capable of ATP hydrolysis (https://pubmed.ncbi.nlm.nih.gov/39695695/). To the best of our knowledge, this is the first time this activity has been reported for vertebrate Dicers.

In light of these findings, the project focuses on:

• identifying cellular proteins and RNAs that bind to the helicase domain of hDicer,

• determining which of these factors (protein, RNA, or both) influence the ATPase activity of hDicer - and how,

• establishing the potential biological significance of hDicer’s ATPase activity.

The project plans to utilize modern molecular biology and biophysics techniques, including:

• mass spectrometry to identify proteins interacting with hDicer,

• fluorescence and confocal microscopy to visualize hDicer•protein and hDicer•RNA complexes in cells,

• in vitro studies on the ATPase activity of hDicer,

• cryo-electron microscopy to analyze the structure of selected hDicer complexes.

The project will provide new insights into the regulatory mechanisms associated with Dicer proteins, contributing to a better understanding of the complex functions of multidomain proteins in the cell.

Research shall be carried out within the project 2024/55/B/NZ2/02771, entitled “The complex nature of multidomain proteins: the unmasked activity of human Dicer ribonuclease – expect the unexpected”, funded by the National Science Centre.

IBCH PAS is one of the leading scientific units in Poland and conducts research activities in the field of chemistry, molecular biology and biomedicine. The Institute provides access to technologically advanced research equipment.