Functional evolution of the microfibril-associated glycoproteins

Area of Science:

• Biochemistry
• Evolutionary Biology
• Molecular Biology

Background:

• Microfibril-associated glycoproteins (MAGPs) are essential components of the fibrillin-based microfibrillar complex.
• MAGPs play vital roles in microfibril and elastic fiber structure, homeostasis, and vascular development across vertebrates.
• The evolutionary history and conservation extent of MAGP1 and MAGP2 in vertebrates remain largely unknown.

Purpose of the Study:

• To investigate the evolutionary history and conservation of microfibril-associated glycoproteins (MAGPs) in vertebrates.
• To identify the earliest homologs of MAGP1 and MAGP2 across diverse vertebrate lineages.
• To elucidate the evolutionary trajectories and selective pressures acting on MAGP1 and MAGP2.

Main Methods:

• Sequence similarity searches were performed on nucleotide and protein databases to identify MAGP homologs.
• Phylogenetic and phylogenomic analyses were employed to reconstruct evolutionary relationships and assess synteny conservation.
• Functional divergence estimates and nucleotide substitution models were used to analyze selective constraints.

Main Results:

• MAGP1 homologs were identified in monotremes, birds, elasmobranchs, and agnathans, indicating an ancient origin.
• MAGP2 homologs were found in marsupials, birds, and teleosts, suggesting evolution from a gene duplication event.
• MAGP2 exhibits rapid evolution in bony vertebrates, potentially driven by relaxed selective constraints and correlated evolution with Notch1, while MAGP1 remained under strong purifying selection.

Conclusions:

• MAGP1 and MAGP2 have distinct evolutionary histories, with MAGP1 being ancient and MAGP2 evolving later within vertebrates.
• The rapid evolution of MAGP2 in bony vertebrates represents a significant innovation, influenced by interactions with developmental regulators.
• Understanding the evolutionary dynamics of MAGPs provides insights into the structural integrity and development of elastic fibers.