Disclosed are fusion proteins, polynucleotides that encode the disclosed fusion proteins, and methods for expressing and autoprocessing of the disclosed fusion proteins to obtain a target protein. The disclosed fusion proteins include an autoproteolytic cysteine protease fused to a heterologous polypeptide, which may be isolated as the target protein. Preferably, the protease activity of the cysteine protease is inducible. Suitable autoproteolytic cysteine proteases for the fusion proteins include the cysteine protease of the Vibrio cholerae RTX toxin.