Which proteins are responsible for exporting proteins from the nucleus?

Exportins are specialized proteins that play a crucial role in the process of transporting proteins out of the nucleus. They function by recognizing specific signal sequences on proteins destined for export, known as nuclear export signals (NES). Once bound to the protein, exportins facilitate the export process by forming a complex that interacts with the nuclear pore complex, allowing the protein to move through the nuclear envelope and into the cytoplasm.

This transport mechanism is vital for the regulation of various cellular processes, including gene expression, as it controls which proteins can enter or leave the nucleus in response to physiological needs. Exportins often work in conjunction with other factors, such as small GTPases, to ensure that the export process is efficient and regulated.

In contrast, the other options listed have different roles: chaperones assist in protein folding and stabilization, importins are responsible for bringing proteins into the nucleus, and translocases are involved in the transport of proteins across mitochondrial and plastid membranes, not specifically related to nuclear export.