Cytoskeletal proteins in the cell nucleus: a special nuclear actin perspective

Abstract

The emerging role of cytoskeletal proteins in the cell nucleus has become a new frontier in cell biology. Actin and actin-binding proteins regulate chromatin and gene expression, but importantly they are beginning to be essential players in genome organization. These actin-based functions contribute to genome stability and integrity while affecting DNA replication and global transcription patterns. This is likely to occur through interactions of actin with nuclear components including nuclear lamina and subnuclear organelles. An exciting future challenge is to understand how these actin-based genome-wide mechanisms may regulate development and differentiation by interfering with the mechanical properties of the cell nucleus and how regulated actin polymerization plays a role in maintaining nuclear architecture. With a special focus on actin, here we summarize how cytoskeletal proteins operate in the nucleus and how they may be important to consolidate nuclear architecture for sustained gene expression or silencing.

FIGURE 1:

Actin has been implicated in many nuclear tasks including chromatin regulation, transcription, and long-range chromosome movement. Recent evidence indicates that actin-based mechanisms impact cellular functions as different as DNA damage and nuclear reprogramming during differentiation. Because these functions are dependent on efficient organization of genomic architecture, we suggest a model where actin is a primary regulator of the functional architecture of the genome. We speculate that rounds of actin polymerization and depolymerization play an important role in facilitating interactions with different nuclear machinery.