XPO6

XPO6, or exportin-6, is a protein encoded by the XPO6 gene in humans. It belongs to the karyopherin beta family of nuclear transport receptors and functions as a nuclear export receptor that transports cargo from the nucleus to the cytoplasm in a Ran GTPase–dependent manner.

The principal cargo of XPO6 is actin monomers, typically in complex with profilin, which are exported from the nucleus to the cytoplasm. By regulating the nuclear pool of actin, XPO6 influences processes that depend on nuclear actin, including transcription, chromatin remodeling, and possibly DNA repair. While actin–profilin complexes are a major cargo, XPO6 is thought to participate in exporting other proteins in a Ran-dependent manner, consistent with the broader role of exportins in coordinating nucleocytoplasmic transport.

Structurally, XPO6 is a large protein predicted to contain HEAT repeats, a characteristic feature of many karyopherin family members that enables cargo recognition and transport through the nuclear pore complex. It is widely expressed across tissues, reflecting a fundamental role in cellular homeostasis.

Physiological and research relevance is centered on how XPO6 activity governs the distribution of actin between the nucleus and cytoplasm, thereby affecting gene expression programs and cellular responses to stress. Experimental manipulation of XPO6 levels can alter nuclear actin concentrations and influence transcriptional outputs, making XPO6 a focus in studies of nuclear actin dynamics and nucleocytoplasmic transport.

See also: actin, profilin, RanGTP, karyopherin, nuclear transport.