γ-Tubulin Complexes and Fibrillar Arrays: Two Conserved High Molecular Forms with Many Cellular Functions

• Published in: Cells (Basel, Switzerland) Switzerland), 2021-04, Vol.10 (4), p.776
• Main Authors: Chumová, Jana, Kourová, Hana, Trögelová, Lucie, Daniel, Geoffrey, Binarová, Pavla
• Format: Article
• Language: English
• Subjects: Amino acids; Biochemistry and Molecular Biology; Biokemi och molekylärbiologi; Cell division; Centrosomes; fibrillar arrays; Filaments; Fungi; gamma-tubulin; gamma-tubulin complexes; Hypotheses; Insects; Microtubules; Nucleation; Plant cells; plants; Proteins; Regulation; Review; Tubulin
• ISSN: 2073-4409; 2073-4409
• DOI: 10.3390/cells10040776

Higher plants represent a large group of eukaryotes where centrosomes are absent. The functions of γ-tubulin small complexes (γ-TuSCs) and γ-tubulin ring complexes (γ-TuRCs) in metazoans and fungi in microtubule nucleation are well established and the majority of components found in the complexes are present in plants. However, plant microtubules are also nucleated in a γ-tubulin-dependent but γ-TuRC-independent manner. There is growing evidence that γ-tubulin is a microtubule nucleator without being complexed in γ-TuRC. Fibrillar arrays of γ-tubulin were demonstrated in plant and animal cells and the ability of γ-tubulin to assemble into linear oligomers/polymers was confirmed in vitro for both native and recombinant γ-tubulin. The functions of γ-tubulin as a template for microtubule nucleation or in promoting spontaneous nucleation is outlined. Higher plants represent an excellent model for studies on the role of γ-tubulin in nucleation due to their acentrosomal nature and high abundancy and conservation of γ-tubulin including its intrinsic ability to assemble filaments. The defining scaffolding or sequestration functions of plant γ-tubulin in microtubule organization or in nuclear processes will help our understanding of its cellular roles in eukaryotes.