18 research outputs found
Topological Analysis of Small Leucine-Rich Repeat Proteoglycan Nyctalopin
Nyctalopin is a small leucine rich repeat proteoglycan (SLRP) whose function is
critical for normal vision. The absence of nyctalopin results in the complete
form of congenital stationary night blindness. Normally, glutamate released by
photoreceptors binds to the metabotropic glutamate receptor type 6 (GRM6), which
through a G-protein cascade closes the non-specific cation channel, TRPM1, on
the dendritic tips of depolarizing bipolar cells (DBCs) in the retina.
Nyctalopin has been shown to interact with TRPM1 and expression of TRPM1 on the
dendritic tips of the DBCs is dependent on nyctalopin expression. In the current
study, we used yeast two hybrid and biochemical approaches to investigate
whether murine nyctalopin was membrane bound, and if so by what mechanism, and
also whether the functional form was as a homodimer. Our results show that
murine nyctalopin is anchored to the plasma membrane by a single transmembrane
domain, such that the LRR domain is located in the extracellular space