Reorganization of the ER in midgut epithelial cells of amino acid fed mosquitoes may be associated with differential abundance of KDEL-containing ER resident proteins, which could provide a clue as to possible whorl-enriched proteins. To test this possibility, we prepared total protein extracts from midguts of unfed and amino acid fed (30 min and 120 min post feeding) mosquitoes, and analyzed the extracts by Western blotting using a KDELspecific antibody as shown in Figure 3 . Four distinct protein bands were observed, two of which appeared to decrease in abundance after feeding (KDEL-2 and KDEL-4), relative to the internal control protein (GAPDH). The KDEL-1 protein was only present in the 30 min sample, whereas the KDEL-3 protein was present in all three protein samples. Since Ae. aegypti protein disulfide isomerase (PDI) has a predicted molecular mass of ,56 kDa, and is a KDEL-containing ER protein known to be expressed in Ae. aegypti midgut cells [26] , we analyzed these same protein extracts with a PDI antibody that recognizes Drosophila melanogaster PDI. Results from these experiments were negative (data not shown), however we could not rule out that antigenic differences between Drosophila and Aedes PDI proteins contributed to the negative result.