Nucleoskeleton proteins for nuclear dynamics

Abstract

The eukaryotic nucleus shows organized structures of chromosomes, transcriptional components and their associated proteins. It has been believed that such a dense nuclear environment prevents the formation of a cytoskeleton-like network of protein filaments. However, accumulating evidence suggests that the cell nucleus also possesses structural filamentous components to support nuclear organization and compartments, which are referred to as nucleoskeleton proteins. Nucleoskeleton proteins including lamins and actin influence nuclear dynamics including transcriptional regulation, chromatin organization and DNA damage responses. Furthermore, these nucleoskeleton proteins play a pivotal role in cellular differentiation and animal development. In this commentary, we discuss how nucleoskeleton-based regulatory mechanisms orchestrate nuclear dynamics.

Mechanotransduction and epigenetic modulations of chromatin: Role of mechanical signals in gene regulation

“…The Arp2/3 complex acts as an actin polymerizer in response to DNA damage, but Arp4, present in the nucleus, suppresses nuclear actin polymerization. 214 Nuclear actin has been shown to interact with emerin and also with the two actin-binding sites of lamin A in INM. 215,216 Utilization of the nuclear actin probe, nuclear Actin Chromobody (nAC), a novel molecular method to visualize actin dynamics inside the nucleus, revealed that integrin signaling is the driving force for nuclear actin polymerization via the LINC complex.…”

“…Formin, an actin‐binding protein, is responsible for nuclear actin polymerization. The Arp2/3 complex acts as an actin polymerizer in response to DNA damage, but Arp4, present in the nucleus, suppresses nuclear actin polymerization 214 . Nuclear actin has been shown to interact with emerin and also with the two actin‐binding sites of lamin A in INM 215,216 .…”

Structural alteration of the nucleus for the reprogramming of gene expression

“…Actin in the nucleus is referred to as nuclear actin. Nuclear actin is involved in a variety of nuclear events, including transcription, chromatin remodelling and DNA damage repair [22,80,81]. Actin dynamically changes its polymerized state between a monomeric globular actin and a polymeric filamentous actin (Factin).…”

“…The most studied nucleoskeleton proteins, lamins, are associated with chromosomal components termed lamina‐associated domains (LADs) [21]. Nuclear actin is also regarded as an emerging key player for organizing nuclear and chromatin structures [22].…”