A Mouse Photoreceptor Proteome Resource Identifies PALS2/MPP6 as a Novel Pan-Cone Photoreceptor Marker

Area of Science:

• Ophthalmology
• Proteomics
• Cell Biology

Background:

• Rod and cone photoreceptors are crucial for vision.
• Understanding their specific protein composition is vital for retinal research.
• Existing proteomic data for these distinct cell types is limited.

Purpose of the Study:

• To generate a quantitative proteome expression resource for mouse rod and cone photoreceptors.
• To enable exploration of cell type-specific proteomic landscapes.
• To identify novel markers for photoreceptor subtypes.

Main Methods:

• Fluorescence-activated cell sorting (FACS) was used to isolate rod and cone photoreceptors.
• Filter-aided sample preparation and in-solution trypsin digestion were employed.
• Mass spectrometry analysis was performed using data-independent acquisition (DIA).

Main Results:

• A comprehensive quantitative proteome resource for mouse rod and cone photoreceptors was generated.
• PALS2 (protein associated with LIN7 2), also known as MPP6 (membrane palmitoylated protein 6), was identified.
• PALS2/MPP6 was found to be present in cone photoreceptors but absent in rod photoreceptors, establishing it as a novel pan-cone photoreceptor marker.
• DIA mass spectrometry provided high protein sequence coverage, enabling insights into photoreceptor type-specific protein isoforms.

Conclusions:

• The study provides a valuable quantitative proteome resource for mouse rod and cone photoreceptors.
• PALS2/MPP6 is identified as a novel and specific marker for pan-cone photoreceptors.
• This resource facilitates deeper understanding of photoreceptor biology and disease mechanisms.