Diversity and Evolution of Sensor Histidine Kinases in Eukaryotes

Area of Science:

• Molecular Biology
• Evolutionary Biology
• Genomics

Background:

• Histidine kinases (HKs) function in two-component systems (TCSs), vital for environmental sensing in prokaryotes and eukaryotes.
• While HKs are well-characterized in prokaryotes, their diversity and distribution in eukaryotes remain incompletely understood.

Purpose of the Study:

• To comprehensively analyze the structural diversity and phylogenetic distribution of HKs across major eukaryotic supergroups.
• To identify novel HK groups and understand their evolutionary trajectories within eukaryotes.

Main Methods:

• Genome-wide searches across 67 eukaryotic species representing diverse phylogenetic lineages.
• Phylogenetic analyses of identified HK protein sequences within each major eukaryotic supergroup.

Main Results:

• Identified 748 predicted HK proteins across the analyzed eukaryotic genomes.
• Characterized previously undescribed eukaryotic HK groups with potential roles in novel physiological processes.
• Discovered HK groups in new supergroups, challenging previous assumptions about their restricted distribution.
• Observed evidence of HK gene appearance, transfer, duplication, and loss across different eukaryotic lineages.

Conclusions:

• This study provides the most extensive overview of eukaryotic HKs to date, establishing a foundation for understanding TCS evolution in Eukaryota.
• The findings highlight the dynamic evolution of HK genes and their expanded functional roles in eukaryotic signaling pathways.