γ-Tubulin–γ-Tubulin Interactions as the Basis for the Formation of a Meshwork

Abstract

In cytoplasm, protein γ-tubulin joins with various γ-tubulin complex proteins (GCPs) to form a heterotetramer γ-tubulin small complex (γ-TuSC) that can grow into a ring-shaped structure called the γ-tubulin ring complex (γ-TuRC). Both γ-TuSC and γ-TuRC are required for microtubule nucleation. Recent knowledge on γ-tubulin with regard to its cellular functions beyond participation in its creation of microtubules suggests that this protein forms a cellular meshwork. The present review summarizes the recognized functions of γ-tubulin and aims to unite the current views on this protein.

Non-Canonical Functions of the Gamma-Tubulin Meshwork in the Regulation of the Nuclear Architecture

“…In the cytoplasm and nucleus, three main families of structures ensure these functions-actin filaments, intermediate filaments, and MTs-and the LINCs are one of the linking structures between compartments [80]. In addition, the γtubulin meshwork establishes a connection between the cytoplasmic and nuclear compartments [14,17,18].…”

“…γTubulin1 is a ubiquitously expressed protein, whereas γtubulin2 is highly expressed in the brain [87]. γTubulin1 and γtubulin2 proteins exhibit an amino acid level identity of 97%, and the main differences in the protein sequence are localized to the DNA binding domain at the C-terminus of the protein [14,88].…”

“…In contrast to γstrings, which are static structures, γtubules and MTs are temperature-sensitive polar structures that vary both in size and location, and both can emanate from centrosomes ( Figure 2) [16,95]. [14,17,18]. In the nucleus, γtubulin interacts with laminB (lamina) [17], the nucleoporin embryonic large molecule derived from yolk sac (ELYS), which is part of the nuclear pore complex (NPC) [99], the inner nuclear membrane (INM) protein Samp1 [104], the chromatin associated proteins Rad51 [106] and C53 [100], and the transcription factor E2 promoter binding factor (E2F)1 [88].…”

“…Within eukaryotic cells, the self-polymerizing ability of the protein gamma (γ) tubulin results in the formation of an interlinked protein meshwork, composed of γstrings, γtubules, and centrosomes, in both the cytosol (including all cellular organelles) and the nuclear compartment [14][15][16][17][18]. Here, we review and discuss the latest knowledge regarding changes that arise in the nuclear architecture of healthy cells and under pathological conditions, and, more specifically, consider the particular involvement of γtubulin in the modulation of the biology of the nuclear compartment.…”

Non-Canonical Functions of the γTubulin Meshwork in the Regulation of the Nuclear Architecture

“…Within eukaryotic cells, the self-polymerizing ability of the protein gamma () tubulin results in the formation of an interlinked protein meshwork, composed of strings, tubules, and centrosomes, in both the cytosol (including all cellular organelles) and the nuclear compartment [10][11][12][13][14]. Here, we review and discuss the latest knowledge regarding changes that arise in the nuclear architecture of healthy cells and under pathological conditions, and, more specifically, consider the particular involvement of tubulin in the modulation of the biology of the nuclear compartment.…”