Septins From Protists to People.

Brent Shuman,Michelle Momany

doi:10.3389/fcell.2021.824850

Abstract

Septin GTPases form nonpolar heteropolymers that play important roles in cytokinesis and other cellular processes. The ability to form heteropolymers appears to be critical to many septin functions and to have been a major driver of the high conservation of many septin domains. Septins fall into five orthologous groups. Members of Groups 1–4 interact with each other to form heterooligomers and are known as the “core septins.” Representative core septins are present in all fungi and animals so far examined and show positional orthology with monomer location in the heteropolymer conserved within groups. In contrast, members of Group 5 are not part of canonical heteropolymers and appear to interact only transiently, if at all, with core septins. Group 5 septins have a spotty distribution, having been identified in specific fungi, ciliates, chlorophyte algae, and brown algae. In this review we compare the septins from nine well-studied model organisms that span the tree of life (Homo sapiens, Drosophila melanogaster, Schistosoma mansoni, Caenorhabditis elegans, Saccharomyces cerevisiae, Aspergillus nidulans, Magnaporthe oryzae, Tetrahymena thermophila, and Chlamydomonas reinhardtii). We focus on classification, evolutionary relationships, conserved motifs, interfaces between monomers, and positional orthology within heteropolymers. Understanding the relationships of septins across kingdoms can give new insight into their functions.

Highlights

Septin GTPases form nonpolar heteropolymers and are a component of the cytoskeleton (Mostowy and Cossart 2012)
We will do this by comparing septins from nine model systems (Figure 1), focusing on classifications based on evolutionary relationships and conserved motifs, including interfaces
Septins have duplicated and diversified from their common evolutionary ancestor to perform an amazing array of important functions across species from protists to people

Summary

Introduction

Septin GTPases form nonpolar heteropolymers and are a component of the cytoskeleton (Mostowy and Cossart 2012). The purpose of this review is to allow researchers to understand the relationships of septins across kingdoms so that they can use insights from other systems to inform their own work We will do this by comparing septins from nine model systems (Figure 1), focusing on classifications based on evolutionary relationships and conserved motifs, including interfaces. We chose these nine organisms because they span the tree of life and are well-studied, but we urge researchers to remember that there is great diversity in septin structure and function and we are covering only a small, though hopefully representative, slice. We apologize to our colleagues whose work might be missed

Objectives

Conclusion