MAGUKs

Bryant This has not been studied in Drosophila. Several Dig-like MAGUKs have been picked up in a yeast two-hybrid screen using as bait the Erb-B4 receptor (Garcia et al 2000), which is the only one of the mammalian EGF receptor family that has a C-terminus predicted to bind to PDZ domains. This interaction could be involved in controlling receptor localization. Potentially it is the same kind of interaction. 

Neuroligin is a protein that binds to the PDZs of PSD95. Neuroligin reaches into the synaptic cleft and interacts with [3-neurexin, a protein that reaches into the synaptic cleft from the presynaptic side P-neurexin is anchored presynaptically to the PDZ domain of another MAGUK, CASK. This arrangement connects the pre-and postsynaptic elements and stabilizes the synapse mechanically. 

MAGUK membrane-associated guanylyl kinase homolog NET norepinephrine transporter... 

Itoh, M., et al. 1999. Direct binding of three tight junction associated MAGUKs, ZO-1, ZO-2 and ZO-3 with the COOH termini of claudins. J Cell Biol 147 1351. 

The calcium channel p subunit is the only calcium channel subunit for which there is crystal structure information. The core of this subunit is homologous to membrane-associated guanylate kinases (MAGUKs), with conserved, interacting SH3 and guanylate kinase (GK) domains (Takahashi et al. 2004). Residues in the... 

Cai C, Li H, Rivera C, Keinanen K. 2006. Interaction between SAP97 and PSD-95, two Maguk proteins involved in synaptic trafficking of AMPA receptors. J Biol Chem 281 4267-4273. 

Table 2. Distribution of PDZ domain-containing proteins in neuronal multiprotein complexes. As MAGUK proteins and other PDZ domain-containing proteins provide important scaffolding functions in protein complexes their distribution was analysed. The most widely used PDZ domain-containing proteins are DLGH3 and SAP97. The differential use of these proteins in complexes containing subtypes of 5-HT receptor highlights the heterogeneity and variability in complexes even in closely related receptors...

Sans N, Prybylowski K, Petralia RS, Chang K, Wang Y-X, et al. 2002. NMDA receptor trafficking depends on an interaction between the MAGUKs and the exocyst complex. Soc. Neurosci. Abstr. In press... 

McGee AW, Topinka JR, Hashimoto K, Petralia RS, Kakizawa S, et al. 2001. PSD-93 knock-out mice reveal that neuronal MAGUKs are not required for development or function of parallel fiber synapses in cerebellum. J. Neurosci. 21 3085-91... 

The first of the four zones includes the postsynaptic membrane and approximately the upper half of the PSD. In this zone, preferential labeling is seen for all ionotropic glutamate receptors and for the associated proteins known as membrane-associated guanylate kinases (MAGUKs) including PSD-95, SAP-102, PSD-93, and SAP-97 (Valtschanoff et al., 1999) (Figs. 7 and 8). The second zone includes approximately the bottom half (for the purpose... 

PSD-95/S AP90 belongs to the MAGUK superfamily of proteins, which are characterized by the presence of PDZ domains, an SH3 domain and a guanylate kinase-like (GK) domain (Cho et al., 1992 Kistner et al., 1993). PDZ domains are modular protein domains of 90 amino acids that are specialized for binding to C-terminal peptides in a sequence-specific... 

The list of proteins that can interact with the cytoplasmic tail of NMDA receptor subunits is growing. Here we discuss a few examples that were not mentioned in earlier sections. S-SCAM, a protein with an N-terminal GK domain followed by two WW motifs and five PDZ domains, has been shown to bind to NR2 subunits with its fifth PDZ domain (Hirao et al., 1998). S-SCAM belongs to a family of proteins that includes AIPl and MAGI, which are distantly related to the MAGUK proteins. MALS, a mammalian homolog of LIN-7, can also bind to NR2 subunits via a PDZ-C-terminus interaction (Jo et al., 1999). The significance of these interactions for NMDA receptor function in vivo remains to be determined. 

The GluRl subunit of AMPA receptors does not bind to GRIP, ABP, or PICKl, but its C-terminus has been recently shown to associate with SAP97, a member of the PSD-95 family of MAGUKs (Leonard et al., 1998). Since SAP97 is reported to be predominantly presynaptic (Muller et al., 1995), however, the physiological significance of this interaction is uncertain. 

Haskins J, Gu L, Wittchen ES, Hibbard J, Stevenson BR. ZO-3, a novel member of the MAGUK protein family found at the tight junction, interacts with ZO-1 and occludin. J Cell Biol 1998 141 199-208. 

Itoh M, Morita K, Tsukita S. Characterization of ZO-2 as a MAGUK family member associated with tight as well as adherens junctions with a binding affinity to occludin and alpha catenin. J Biol Chem 1999 274 5981-5986. 

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