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The prenyl-binding protein PrBP/δ: a chaperone participating in intracellular trafficking

Houbin Zhang1, Ryan Constantine, Jeanne M Frederick

  • 1Department of Ophthalmology, John A. Moran Eye Center, University of Utah Health Science Center, 65 Mario Capecchi Dr., Salt Lake City, UT 84132, USA.

Vision Research
|September 11, 2012
PubMed

Insights

Prenylated protein chaperone PrBP/δ (prenyl-binding protein delta) is crucial for transporting specific proteins in the eye. Its absence causes progressive vision loss in mice due to impaired protein trafficking.

Area of Science:

  • Molecular and Cellular Biology
  • Neuroscience
  • Genetics

Background:

  • PrBP/δ is a ubiquitous protein chaperone involved in prenylated protein transport.
  • It possesses an immunoglobulin-like fold facilitating lipid binding and interaction with various partners.
  • PrBP/δ binds C-terminal prenyl chains (C15 and C20) of phototransduction proteins and Ras superfamily GTP-binding proteins.

Purpose of the Study:

  • To investigate the role of PrBP/δ in the trafficking of prenylated proteins within the visual system.
  • To determine the consequences of PrBP/δ deficiency on retinal structure and function.

Main Methods:

  • Targeted deletion of the mouse Pde6d gene to create PrBP/δ knockout mice.
  • Analysis of protein trafficking to photoreceptor outer segments.
  • Assessment of retinal structure and function in knockout versus wild-type mice.

Main Results:

  • Deletion of Pde6d impaired the trafficking of farnesylated GRK1 and geranylgeranylated cone PDE6 to outer segments.
  • Trafficking of rod and cone transducin was largely unaffected.
  • PrBP/δ deficiency led to progressive cone-rod dystrophy in Pde6d(-/-) mice.

Conclusions:

  • PrBP/δ is essential for the proper localization of specific prenylated proteins, including GRK1 and cone PDE6, within photoreceptor outer segments.
  • Dysfunctional PrBP/δ-mediated protein transport results in retinal degeneration, specifically cone-rod dystrophy.
  • These findings highlight PrBP/δ's critical role in maintaining visual system integrity.

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