Septins From Protists to People.

Area of Science:

• Cell Biology
• Evolutionary Biology
• Biochemistry

Background:

• Septin GTPases are essential proteins forming heteropolymers vital for cellular processes like cytokinesis.
• Their ability to form heteropolymers drives the conservation of septin domains across species.
• Septins are classified into five groups, with Groups 1-4 forming core heterooligomers found in fungi and animals.

Purpose of the Study:

• To compare septins from nine diverse model organisms spanning the tree of life.
• To analyze septin classification, evolutionary relationships, and conserved motifs.
• To investigate monomer interfaces and positional orthology within septin heteropolymers.

Main Methods:

• Comparative analysis of septin sequences and structures.
• Phylogenetic analysis to determine evolutionary relationships.
• Identification and comparison of conserved motifs and interaction interfaces.

Main Results:

• Core septins (Groups 1-4) exhibit conserved structures and positional orthology across fungi and animals.
• Group 5 septins are distinct, not forming canonical heteropolymers, and have a sporadic distribution.
• Evolutionary relationships and conserved functional domains were elucidated across the studied species.

Conclusions:

• Understanding septin evolution and relationships across kingdoms provides insights into their diverse cellular functions.
• The distinction between core septins and Group 5 septins highlights functional divergence.
• Comparative analysis is key to deciphering the complex roles of septins in cell biology.