The present invention provides a protease cleavage resistant molecules comprising Shiga toxin effector polypeptide capable of exhibiting a strong Shiga toxin function (e.g., intracellular pathways determined and cytotoxicity). The invention, specific cell types, for example, to infected or malignant cells to the target protease cleavage resistant also provides cell targeting molecules. Specific molecules of the present invention are cytotoxic, specific cell targeting molecules of the present invention, specific cell types targeted killing, as well as various, including cancer, tumors, developmental abnormalities, immune disorders and microbial infections diseases, can be used in the treatment of disorders and conditions. Specific cell targeting molecules of the present invention exhibits protease cleavage susceptibility, wild-type, in vivo tolerance improvement compared with related cell targeting molecule comprising a Shiga toxin effector polypeptide. Cell targeting molecules of the present invention, for example an antigen, further substances, such as cytotoxic drugs and detection accelerator may be delivered to the interior of the target cells.