Analysis of Plant-Specific ANTH Domain-Containing Protein in Marchantia polymorpha.

Area of Science:

• Cell Biology
• Evolutionary Biology
• Molecular Biology

Background:

• Membrane trafficking is crucial for cellular transport, with its machinery diversifying across eukaryotic lineages.
• Adaptor protein families like AP180 N-terminal homology (ANTH) proteins regulate vesicle formation and cargo sorting during clathrin-mediated endocytosis.
• Plant evolution shows significant expansion and diversification of ANTH proteins compared to yeast and animals.

Purpose of the Study:

• To investigate the diversification of ANTH proteins during plant evolution.
• To characterize a novel, plant-unique ANTH protein, PICALM-K, identified in Marchantia polymorpha.
• To elucidate the function of MpPICALM-K in M. polymorpha.

Main Methods:

• Genomic analysis to identify ANTH protein repertoires in different plant species.
• Genetic and cell biology approaches to characterize MpPICALM-K in Marchantia polymorpha.
• Artificial intelligence (AI)-based methods for protein analysis.

Main Results:

• Marchantia polymorpha possesses a simpler repertoire of canonical ANTH proteins but encodes a unique non-canonical ANTH protein with a putative kinase domain, named PICALM-K.
• PICALM-K exhibits ancient origins with evidence of multiple secondary losses in other plant lineages.
• MpPICALM-K demonstrates a distinct, flagella-related function in spermatozoids, differing from canonical ANTH proteins.

Conclusions:

• ANTH proteins have undergone significant functional diversification throughout evolution.
• PICALM-K represents a plant-unique ANTH protein, likely arising through neofunctionalization via exon shuffling.
• The discovery highlights novel roles for ANTH proteins beyond canonical endocytic pathways in plants.