An interaction between leukocyte cell-derived chemotaxin 2 and transferrin of ayu, Plecoglossus altivelis

Yeast two-hybrid (Y2H) screens were used to test for interactions between leukocyte cell-derived chemotaxin 2 (LECT-2) and a liver cDNA expression library of ayu, Plecoglossus altivelis. Of the 9 independent interacting clones identified, 7 were identical and closely related to transferrin (To genes of fish, while the other two were related to c-type lectin genes. The interaction between ayu Tf (aTf) and ayu LECT2 (aLECT2) was confirmed by in vitro co-immunoprecipitation of the two proteins. Y2H assays using different parts of the two proteins showed that the segment aTf185-289 was not involved in the interaction with mature aLECT2, while the transit peptide of aLECT2 couldn't interact with entire aTf. Computer analysis revealed that aTf185-289, which contained two iron binding residues, Tyr197 and His253, was located at the N-terminus of aTf N-lobe. Strong interactions were also determined between LECT2 and Tf from the same animal, such as croceine croaker, Larimichthys crocea and mouse, Mus musculus. However, no cross-species interactions were determined. Based on published data, the Tf-LECT2 interaction is suggested to be most possibly involved in the body's defense against infection. (C) 2009 Elsevier Ltd. All rights reserved.