Nucleoporinen

Nucleoporins are a family of proteins that make up the nuclear pore complex (NPC). The NPC is a large, intricate molecular machine that spans the nuclear envelope, regulating the transport of molecules between the nucleus and the cytoplasm of eukaryotic cells. Nucleoporins are essential for maintaining cellular function, as they control the passage of everything from small molecules to large proteins and RNA.

There are over 30 different types of nucleoporins, each with specific roles in the structure and function of the NPC. These proteins are characterized by their repetitive amino acid sequences, particularly the FG (phenylalanine-glycine) repeats. These FG repeats are thought to form a selective barrier within the central channel of the NPC, allowing for the passive diffusion of small molecules while actively gating the transport of larger cargo.

The NPC itself is a complex assembly of nucleoporins, forming a roughly spherical structure with a diameter of about 120 nanometers. It has a central channel through which transport occurs, flanked by outer rings that anchor the NPC to the nuclear envelope and inner rings that connect to the nuclear lamina. The precise arrangement and interactions of nucleoporins are critical for the NPC's ability to discriminate between molecules that should enter or leave the nucleus.

Dysfunction of nucleoporins and the NPC has been linked to a variety of diseases, including cancer, viral infections, and neurodegenerative disorders. Understanding the structure and function of nucleoporins is therefore crucial for developing new therapeutic strategies. Research continues to uncover the intricate details of nucleoporin organization and their dynamic roles in nuclear transport and cellular regulation.