A nuclear localizing signal (NLS) is an amino acid sequence which acts like a 'tag' on the exposed surface of a protein. This sequence is used to confine the protein to the cell nucleus through the Nuclear Pore Complex and to direct a newly synthesized protein into the nucleus via its recognition by cytosolic nuclear transport receptors. Typically, this signal consists of a few short sequences of positively charged lysines or arginines. Different nuclear localized proteins may share the same NLS.

Genetically the NLS results from transcription of a nuclear localizing sequence. Cellular processes and protein function may be studied by adding a known NLS sequence to a gene, confining the chimeric protein product to the nucleus. An NLS is the opposite of a nuclear export signal, which confines proteins to the cytosolic face of the nuclear membrane. Typically the NLS will have a sequence (NH2)-Pro-Pro-Lys-Lys-Lys-Arg-Lys-Val-(COOH).

Cell biology | Molecular genetics

Nukleares Lokalisierungssignal