A novel human dynactin-associated protein, dynAP, promotes activation of Akt, and ergosterol-related compounds induce dynAP-dependent apoptosis of human cancer cells

Tatsuki Kunoh, Takanori Noda, Koichi Koseki, Masayuki Sekigawa, Motoki Takagi, Kazuo Shin-ya, Naoki Goshima, Shun Ichiro Iemura, Tohru Natsume, Shu Ichi Wada, Yukio Mukai, Shinji Ohta, Ryuzo Sasaki, Tamio Mizukami

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7 Citations (Scopus)

Abstract

There are several human genes that may encode proteins whose functions remain unknown. To find clues to their functions, we used the mutant yeast defective in Mad2, a component of the spindle checkpoint complex. Phenotypes that were provoked by the expression of a human C18orf26 protein in the mutant yeast encouraged further characterization of this protein in human cells. This protein was designated dynAP (dynactin-associated protein) because of its interaction with dynactin subunits that comprised a microtubule-based motor protein complex. The dynAP is a transmembrane protein localizing to Golgi apparatus and plasma membrane in a microtubule-dependent manner. This protein was expressed in half of human cancer cell lines but barely in normal human fibroblasts tested. The SV40-transformed fibroblasts expressed dynAP. Importantly, the expression of dynAP activated Akt (also known as protein kinase B) by promoting Ser473 phosphorylation required for the full activation, whereas knockdown of dynAP abolished this activation. The ergosterol-related compounds identified by the yeast cell-based high-throughput screen abrogated activation of Akt and induced apoptosis in a dynAP-dependent manner. We propose a possible advantage of dynAP expression in cancer cells; the survival of cancer cells that express dynAP is supported by dynAP-induced activation of Akt, sustaining high rates of proliferation. The inactivation of dynAP by the selected compounds nullifies this advantage, and thereby, the apoptotic machinery is allowed to operate. Taken together, dynAP can be a new target for cancer therapy, and the selected chemicals are useful for developing a new class of anticancer drugs.

Original languageEnglish
Pages (from-to)2934-2942
Number of pages9
JournalMolecular cancer therapeutics
Volume9
Issue number11
DOIs
Publication statusPublished - Nov 1 2010

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

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    Kunoh, T., Noda, T., Koseki, K., Sekigawa, M., Takagi, M., Shin-ya, K., Goshima, N., Iemura, S. I., Natsume, T., Wada, S. I., Mukai, Y., Ohta, S., Sasaki, R., & Mizukami, T. (2010). A novel human dynactin-associated protein, dynAP, promotes activation of Akt, and ergosterol-related compounds induce dynAP-dependent apoptosis of human cancer cells. Molecular cancer therapeutics, 9(11), 2934-2942. https://doi.org/10.1158/1535-7163.MCT-10-0730