PTEN 2, a Golgi-associated testis-specific homologue of the PTEN tumor suppressor lipid phosphatase

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Y Wu1, D Dowbenko, M T Pisabarro

  • 1Department of Molecular Oncology, Genentech, Inc., South San Francisco, California 94080, USA.

The Journal of Biological Chemistry
|March 30, 2001
PubMed

Insights

Researchers discovered PTEN 2, a novel testis-specific protein phosphatase. This protein, localized to the Golgi apparatus, may play a role in spermatocyte differentiation.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Background:

  • The tumor suppressor PTEN is a phosphatidylinositol phospholipid phosphatase that regulates protein kinase B/Akt signaling.
  • PTEN indirectly down-regulates the activity of Akt survival kinases.

Purpose of the Study:

  • To identify and characterize a novel homologue of PTEN.
  • To investigate the function and localization of the PTEN homologue, termed PTEN 2.

Main Methods:

  • Sequence database analysis to identify PTEN homologues.
  • Transcript analysis to determine PTEN 2 expression patterns.
  • Molecular modeling to predict PTEN 2 structure and function.
  • Enzymatic assays to determine PTEN 2 substrate specificity.

Main Results:

  • A highly conserved PTEN homologue, PTEN 2, was identified with unique features including transmembrane domains.
  • PTEN 2 is specifically expressed in the testis, localized to secondary spermatocytes and the Golgi apparatus.
  • PTEN 2 functions as a phospholipid phosphatase, with substrate specificity similar to PTEN, preferring phosphatidylinositol 3,5-phosphate.
  • PTEN 2's localization and enzymatic activity suggest a role in vesicular trafficking.

Conclusions:

  • PTEN 2 is a testis-specific, Golgi-localized phospholipid phosphatase.
  • PTEN 2 may be involved in regulating vesicular trafficking during spermatocyte differentiation.
  • PTEN 2 represents a novel player in male reproductive biology.

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