POT1b regulates phagocytosis and NO production by modulating activity of the small GTPase Rab5

Makoto Hagiwara, Toshinori Komatsu, Shin suke Sugiura, Ryutaro Isoda, Hiroyuki Tada, Naomi Tanigawa, Yoshiko Kato, Naoyuki Ishida, Kaoru Kobayashi, Kenji Matsushita

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


The protection of telomeres 1 (POT1) protein is a 75-kDa protein that plays an important role in telomere protection, which is related to telomere elongation. Although POT1 is present in and acts in the nuclei, little is known about the functions of POT1 in the cytosol. We here examined the role of POT1b in phagocytosis in a macrophage-like RAW 264 cell line. We found that POT1 was present in the cytosol, where it was bound to Rab5, which is a protein important for endocytosis. POT1b knockdown in RAW 264 cells increased Rab5 activity and facilitated the phagocytosis of whole cells of Escherichia coli and Staphylococcus aureus. Furthermore, POT1b knockdown enhanced the expression of inducible nitric oxide synthase (iNOS), followed by the promotion of nitric oxide (NO) generation in response to stimulation by bacterial whole cells. These results suggest that POT1b negatively regulates phagocytosis by controlling Rab5 activity and thereby modulates bacteria-induced NO generation. These findings suggest that POT1b participates in innate immune responses.

Original languageEnglish
Pages (from-to)413-417
Number of pages5
JournalBiochemical and biophysical research communications
Issue number3
Publication statusPublished - 2013 Sept 27
Externally publishedYes


  • Inflammation
  • Nitric oxide
  • POT1b
  • Phagocytosis
  • Rab5

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology


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