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Manganese-induced trafficking and turnover of the cis-Golgi glycoprotein GPP130

Somshuvra Mukhopadhyay1, Collin Bachert, Donald R Smith

  • 1Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA.

Molecular Biology of the Cell
|February 5, 2010
PubMed

Insights

Manganese (Mn) exposure triggers the movement of Golgi phosphoprotein of 130 kDa (GPP130) to cellular compartments for degradation. The protein's stem domain acts as a novel Mn sensor in the Golgi lumen.

Area of Science:

  • Cell Biology
  • Neuroscience
  • Biochemistry

Background:

  • Manganese is essential but neurotoxic at high levels.
  • Mechanisms of manganese homeostasis in mammalian cells are poorly understood.
  • Yeast studies show cytosolic manganese alters protein localization.

Purpose of the Study:

  • Investigate manganese homeostasis in mammalian cells.
  • Identify proteins involved in manganese regulation.
  • Determine the role of GPP130 in manganese response.

Main Methods:

  • Observed GPP130 localization changes in response to extracellular manganese.
  • Utilized Rab-7 dependent pathway analysis.
  • Performed domain-specific analysis of GPP130.

Main Results:

  • Low extracellular manganese induced GPP130 redistribution from the Golgi to multivesicular bodies.
  • GPP130 was degraded in lysosomes via a Rab-7 dependent pathway.
  • The lumenal stem domain of GPP130 is crucial for manganese sensing and response.

Conclusions:

  • The stem domain of GPP130 functions as a novel manganese sensor in the Golgi lumen.
  • GPP130 trafficking is a key component of manganese regulation in mammalian cells.
  • This finding provides new insights into cellular manganese homeostasis.

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