Hypothetical model of AKR1B10 secretion. The entire secretory process of AKR1B10 includes trafficking of AKR1B10 to the lysosomal membrane, import into the lysosomal lumen, and lysosomal exocytosis. A portion of HSP90 enters into lysosomes and is secreted with AKR1B10, but the other remains outside of lysosomes and is recycled. B10, AKR1B10; CD, cathepsin D.