“…For example, the PDZ [postsynaptic density 95 (PSD-95)/Discs Large (DLG)/zona occludens-1]-domain scaffold DLG, a PSD-95 homolog, is involved in the localization of many synaptic proteins (Lahey et al, 1994;Budnik et al, 1996;Guan et al, 1996;Tejedor et al, 1997;Thomas et al, 1997Thomas et al, , 2000Mathew et al, 2002;Roche et al, 2002) but plays a specific role in B-class GluR regulation: GluRIIB abundance correlates with DLG level, but GluRIIA localization is unaffected in dlg mutants . Similarly, the Rho-type guanine nucleotide exchange factor dPix (the Drosophila homolog of the Pak interacting exchange factor) (Werner and Manseau, 1997;Hakeda-Suzuki et al, 2002), its interacting Drosophila p-21 activated kinase (dPak), a serine threonine kinase activated by GTPases Rac and cell division cycle 42 (Harden et al, 1996;Newsome et al, 2000;Mentzel and Raabe, 2005), and a dPak binding partner, the adaptor Dreadlocks (Dock; Nck homolog) (Rao and Zipursky, 1998;Buday et al, 2002;Ang et al, 2003;Rao, 2005), are all required to facilitate synaptic expression of A-class GluRs, but GluRIIB is reportedly not affected in mutants of this pathway (Parnas et al, 2001;Albin and Davis, 2004). Trafficking mechanisms likely involve GluR tethering to the cytoskeleton.…”