FIG 7.

Mutant of MGL1 lacking 15 amino acids from its cytoplasmic domain retains C-type lectin activity but shows reduced endocytic activity when expressed by Lec1 cells. (A) Nucleotide and deduced amino acid sequences of the cytoplasmic domain of wild-type MGL1 and a deletion mutant lacking 15 amino acids from the cytoplasmic domain (ΔMGL1). The putative internalization domain YENL is underlined. (B) Cell surface expression of MGL1 on Lec1-MGL1 (black histogram), Lec1-ΔMGL1 (gray histogram), or Lec1-ctrl cells (dashed line). (C) Western blot detecting MGL in lysates from Lec1-ΔMGL1 cells. (D) MGL1 on Lec1-ΔMGL1 cells retains lectin function equivalent to that of MGL1 on Lec1-MGL1 cells. Data are representative of 2 independent experiments. (E) Reduced endocytic capacity of MGL1 expressed on Lec1-ΔMGL1 cells. MGL1-mediated endocytosis was determined as described in Materials and Methods. The asterisk indicates cell surface MAb levels that were significantly different between samples after 1 and 30 min (P ≤ 0.05; Student's t test). n.s., not significant.