HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Free Via Open Access Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Xu, F. Z. Articles by Yu, W. Y. Search for Related Content PubMed PubMed Citation Articles by Xu, F. Z. Articles by Yu, W. Y.

The Effect of Site-Directed Mutagenesis of the Ambient Amino Acids of Leucine-Based Sorting Motifs on the Localization of Chicken Invariant Chain

Key Laboratory of Zoonoses of Anhui Province, Anhui Agricultural University, Hefei, 230036, China

² Corresponding author: yuweiyi{at}ahau.edu.cn

Two Leu residues and their ambient amino acid residues are known to exist in the cytosolic tail of chicken invariant chain (Ii), and these play an important role as motifs in mediating the sorting endocytic pathway. We performed 20 mutations via site-directed mutagenesis by the PCR megaprimer method to study the effect of some ambient amino residues of both Leu on the localization of chicken Ii. These mutated fragments were ligated to the vector pEGFP-C1. The recombinant plasmids were transiently transfected into COS-7 cells with Lipofectamine 2000. Furthermore, the fluorescence of located fusion proteins (green fluorescent protein-Ii) was observed with a fluorescence microscope. Our results indicated that 2 Leu-based motifs are required for chicken Ii intracellular localization, and both motifs independently mediate this function of the Ii. The other amino acid residues surrounding both Leu also influence Ii-induced endosomal vacuolation. In addition, we found that Pro¹⁹, which is near the Val¹⁷-Leu¹⁸ motif, was a key residue for chicken Ii intracellular localization. Not only is it critical for endocytic targeting to each Leu, but its unique mutation can also result in altering the function of chicken Ii.

Key Words: chicken invariant chain • site-directed mutagenesis • neighboring amino acid residue • localization

¹ Present address: 130 Changjiang West Road, Hefei, 230036, China.