C-Mannosylated peptides derived from the thrombospondin type 1 repeat interact with Hsc70 to modulate its signaling in RAW264.7 cells

Yoshito Ihara, Shino Manabe, Midori Ikezaki, Yoko Inai, In Sook Lee Matsui, Yuriko Ohta, Eiji Muroi, Yukishige Ito

Research output: Contribution to journalArticlepeer-review

25 Citations (Scopus)


The thrombospondin type 1 repeat (TSR) is a functional module of proteins called TSR superfamily proteins (e.g., thrombospondin, F-spondin, mindin, etc.) and includes a conserved Trp-x-x-Trp (W-x-x-W) motif, in which the first Trp residue is preferably modified by C-mannosylation. We previously reported that synthesized C-mannosylated TSR-derived peptides (e.g., C-Man-WSPW) specifically enhanced lipopolysaccharide-induced signaling in macrophage-like RAW264.7 cells. In this study, we searched for the proteins that bind to C-mannosylated TSR-derived peptides in RAW264.7 cells and identified heat shock cognate protein 70 (Hsc70). The binding affinity of Hsc70 for C-mannosylated peptides in solution was higher than that for the peptides without C-mannose. The binding was influenced by a nucleotide-induced conformational change of Hsc70, and C-mannosylated peptides preferred the substrate-binding domain of Hsc70. Furthermore, in RAW264.7 cells, addition of Hsc70 stimulated cellular signaling to produce tumor necrosis factor-α, via transforming growth factor-β-activated kinase 1, and the Hsc70-induced signaling was enhanced more in the presence of the peptides with C-mannose than that without C-mannose, suggesting functional interaction between Hsc70 and the C-mannosylated peptides in the cells. Together, these results demonstrate a novel function of the C-mannosylation of TSR-derived peptides in terms of interaction with Hsc70 to regulate cellular signaling.

Original languageEnglish
Pages (from-to)1298-1310
Number of pages13
Issue number10
Publication statusPublished - 2010 Oct
Externally publishedYes


  • C-mannosylation
  • Hsc70
  • macrophage
  • thrombospondin

ASJC Scopus subject areas

  • Biochemistry


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