ERG responses to high-frequency flickers require FAT3 signaling in mouse retinal bipolar cells

Area of Science:

• Neuroscience
• Cell Biology
• Vision Science

Background:

• Vision relies on photoreceptor light reception and retinal neuron processing.
• Tissue polarity protein FAT3 is essential for retinal circuit organization, including amacrine cell connectivity and lamination.

Purpose of the Study:

• To investigate the retinal function of FAT3, particularly its role in high-frequency visual responses.
• To elucidate the molecular mechanisms by which FAT3 influences visual processing in bipolar cells.

Main Methods:

• Utilizing Fat3 mutant mice to assess visual function through electroretinography and perceptual tests.
• Investigating the localization and interaction of FAT3 with synaptic proteins like PTPσ and GRIK1 in retinal neurons.

Main Results:

• Fat3 mutant mice exhibited deficits in electroretinography and perceptual responses to high-frequency light flashes.
• These visual defects were not linked to abnormal amacrine cell wiring but rather to FAT3's function in specific bipolar cell subtypes.
• FAT3 was found to bind PTPσ and is necessary for GRIK1 localization at OFF-cone bipolar cell synapses.

Conclusions:

• FAT3 plays a critical role in the function of OFF-cone bipolar cells for high-frequency visual responses.
• The intracellular signaling capacity of FAT3 is vital for transducing visual signals.
• This research expands the known functions of FAT3, highlighting its importance in synaptic transmission for rapid visual processing.