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Internalization of MUC1 by anti-MUC1 antibody from cell membrane through the macropinocytotic pathway

Akinori Hisatsune1, Mitsuru Kawasaki, Hideki Nakayama

  • 1Department of Chemico-Pharmacological Sciences, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto City, Kumamoto 862-0973, Japan. hisatsun@kumamoto-u.ac.jp

Biochemical and Biophysical Research Communications
|August 18, 2009
PubMed

Insights

Antibody binding triggers the internalization and down-regulation of MUC1 (mucin 1) in cancer cells. This process utilizes macropinocytosis, involving MUC1’s cytoplasmic tail and specific cellular pathways.

Area of Science:

  • Cell Biology
  • Cancer Biology
  • Glycoprotein Biology

Background:

  • MUC1 (mucin 1) is a transmembrane glycoprotein overexpressed in various cancers.
  • MUC1's role in cancer progression and its fate after molecular interactions are poorly understood.

Purpose of the Study:

  • To investigate the cellular trafficking of MUC1 upon interaction with an anti-MUC1 antibody.
  • To elucidate the molecular mechanisms underlying MUC1 internalization.

Main Methods:

  • Utilized anti-MUC1 antibody to induce MUC1 internalization in MUC1-expressing cells.
  • Investigated the requirement of MUC1's cytoplasmic tail and the role of specific cellular pathways (Na+/H+ exchanger, caveola/raft, clathrin) using inhibitors.

Main Results:

  • Anti-MUC1 antibody induced MUC1 internalization and down-regulation specifically in MUC1-expressing cells.
  • MUC1 internalization was dependent on its cytoplasmic tail.
  • The process was inhibited by Na+/H+ exchanger inhibitors and caveola/raft-dependent internalization inhibitors, but not by clathrin-dependent internalization inhibitors.

Conclusions:

  • Antibody-induced internalization of MUC1 occurs via the macropinocytotic pathway.
  • This finding provides insights into MUC1 regulation and potential therapeutic targeting in cancer.

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