The type 1 inositol (1,4,5)-trisphosphate receptor (InsP3R1) is an intracellular calcium (Ca2+) release channel that plays an important role in neuronal function. In yeast two-hybrid screen of rat brain cDNA library with the InsP3R1 carboxy-terminal bait we isolated multiple clones of neuronal cytoskeletal protein 4.1N. We mapped the 4.1N-interaction site to a short fragment (50 amino acids) within the carboxy-terminal tail of the InsP3R1 and the InsP3R1-interaction site to the carboxy-terminal domain (CTD) of 4.1N. We established that InsP3R1 carboxy-terminal binds selectively to the CTDΔ alternatively spliced form of the 4.1N protein. In biochemical experiments we demonstrated that 4.1N and InsP3R1 specifically associate in vitro. We showed that both 4.1N and InsP3R1 were enriched in synaptic locations and immunoprecipitated the 4.1N-InsP3R1 complex from rat brain synaptosomes. In biochemical experiments we demonstrated a possibility of InsP3R1-4.1N-CASK-syndecan-2 quaternary complex formation. From our findings we hypothesize that InsP3R1-4.1N association may play a role in InsP3R1 localization or Ca2+ signaling in neurons.
ASJC Scopus subject areas
- Molecular Biology
- Cellular and Molecular Neuroscience
- Cell Biology