Splice variants sites

The NRl family is composed of one subunit with nine different alternatively spliced variants. Block by NMDA channel blockers such as ketamine, MK-801 and phencyclidine is affected by which splice variant of the NRl subunit is involved, probably because the NRl splice variant affects the kinetics of channel activation (the effectiveness of any channel blocker being dependent on how much the channel is open). The glycine binding site is on the NRl subunit and the glutamate binding site is on the NR2 and NR3 subunits. 

Genetic regulation via splice variants and RNA editing further increases receptor heterogeneity the flip/flop versions and the Q/R site 279... 

Genetic regulation via splice variants and RNA editing further increases receptor heterogeneity the flip/flop versions and the Q/R site. Splice variants that impart functional differences and/or different cellular expression patterns have been found for most of the glutamate receptor subunits. The first splice variants to be described were the so-called flip and flop versions of the AMPA... 

Given this combination of internal and C-terminus splice variants and site-specific RNA editing, it appears that four to eight or more mature RNAs can be made from each of the 16 known genes encoding mammalian... 

Calmodulin (CaM), a Ca2+-binding protein, binds directly to the NR1 subunit of the NMDA receptor in a Ca2+-dependent manner. CaM binding occurs at two distinct sites in the COOH -terminal region of NR1 molecule. One CaM binding site is contained within the spliced Cl exon cassette, whereas the other is located in a region common to all NR1 splice variants (Ehlers et al., 1996). Collective evidence suggests that NMDA receptor function can be modulated by CaM binding to the NR1 subunit and this process may be related to activity-dependent feedback inhibition and Ca2+-dependent inactivation of NMDA receptors. 

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