Origin and evolution of lysyl oxidases

Area of Science:

• Biochemistry
• Evolutionary Biology
• Molecular Biology

Background:

• Lysyl oxidases (LOX) are copper-dependent enzymes crucial for extracellular matrix (ECM) remodeling in animals.
• Mammals possess five LOX isoforms (LOX and LOX-like 1-4) with conserved catalytic domains but divergent sequences.
• LOX enzymes catalyze the oxidation of primary amines to aldehydes, facilitating cross-linking of collagen and elastin.

Purpose of the Study:

• To investigate the evolutionary history and origins of the lysyl oxidase (LOX) gene family.
• To understand the diversification of LOX enzymes across different eukaryotic and prokaryotic domains.
• To propose functional roles for different LOX superfamilies in ECM evolution.

Main Methods:

• Genome-wide survey of LOX protein sequences across diverse taxa.
• Phylogenetic analysis to infer evolutionary relationships.
• Comparative analysis of conserved domains and sequence divergence.

Main Results:

• LOX proteins were identified in animals, other eukaryotes, bacteria, and archaea, indicating a pre-metazoan origin.
• LOX genes expanded during metazoan evolution into two main superfamilies: LOXL2/L3/L4 and LOX/L1/L5.
• The LOXL2/L3/L4 group may be involved in basement membrane formation (collagen IV), while LOX/L1/L5 diversified for chordate/vertebrate ECM innovations like elastin and fibronectin.

Conclusions:

• The lysyl oxidase family predates multicellular animals and has undergone significant expansion and diversification.
• Different LOX superfamilies likely played distinct roles in the evolution of structural components in various organisms.
• This study offers a new perspective on the evolutionary trajectory of LOX enzymes and their contribution to biological complexity.