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Deregulated expression of KRAP, a novel gene encoding actin-interacting protein, in human colon cancer cells

Junichi Inokuchi1,2, Misako Komiya1, Iwai Baba1

  • 1Department of Pathology, Research Institute, International Medical Center of Japan, 1-21-1 Toyama, Shinjuku-ku, Tokyo 162-8655, Japan.

Journal of Human Genetics
|December 16, 2003
PubMed

Insights

Researchers discovered Ki-ras-induced actin-interacting protein (KRAP), a novel protein upregulated in colon cancer. KRAP associates with actin filaments and may regulate cellular signals, offering potential therapeutic targets.

Area of Science:

  • Molecular Biology
  • Cancer Research
  • Cell Biology

Background:

  • Ki-ras activation is a key event in colon cancer development.
  • Understanding genes regulated by Ki-ras is crucial for cancer therapy.
  • The function of novel genes in cancer progression needs elucidation.

Purpose of the Study:

  • To identify and characterize novel genes upregulated by activated Ki-ras in colon cancer.
  • To investigate the expression pattern and cellular localization of the identified gene, KRAP.
  • To explore the potential role of KRAP in colon cancer and cellular signaling.

Main Methods:

  • cDNA library screening of human colon cancer HCT116 cells.
  • Gene expression analysis in normal and cancer tissues.
  • Protein characterization using polyclonal antibodies and Western blotting.
  • Immunofluorescence microscopy and cytochalasin E treatment for cellular localization and function.

Main Results:

  • A novel gene, KRAP (Ki-ras-induced actin-interacting protein), was identified and found to be upregulated by activated Ki-ras.
  • KRAP expression was low in normal colon epithelium but deregulated in some colon cancer cells, with strong expression in normal pancreas and testis.
  • KRAP protein (Mr 180,000) was associated with actin filaments and localized to the cell membrane with extracellular regions.

Conclusions:

  • KRAP is a novel gene implicated in colon cancer, linked to Ki-ras activation.
  • KRAP's association with actin filaments and its membrane localization suggest a role in regulating the actin cytoskeleton.
  • KRAP may mediate signals from the extracellular environment, potentially influencing cancer cell behavior.

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