D2 dopamine receptor expression and trafficking is regulated through direct interactions with ZIP

Area of Science:

• Neuroscience
• Molecular Biology
• Biochemistry

Background:

• The D(2) dopamine receptor (DAR) plays a crucial role in neurotransmission.
• Understanding D(2) DAR regulation is vital for neurological research.

Purpose of the Study:

• To identify novel interacting proteins of the D(2) DAR.
• To characterize the functional consequences of D(2) DAR interaction with identified proteins.

Main Methods:

• Yeast two-hybrid screening of a rat brain cDNA library.
• Co-immunoprecipitation assays in mammalian cells and brain tissues.
• Immunohistochemistry and confocal microscopy.

Main Results:

• Protein kinase C-zeta interacting protein (ZIP) was identified as a D(2) DAR interacting protein.
• ZIP specifically binds to the third intracellular loop of D(2) DAR.
• ZIP overexpression leads to D(2) DAR down-regulation, reduced cAMP modulation, and lysosomal accumulation.

Conclusions:

• ZIP physically interacts with the D(2) DAR.
• ZIP mediates the lysosomal trafficking and down-regulation of D(2) DAR.
• ZIP represents a novel regulator of D(2) DAR expression and function.