Many of the broad specificity kinases and phosphation to maintain function (Rosenmund et al., 1994, and tases have been implicated in the regulation of a considreferencestherein). ThePKA-specificinhibitorPKImedierable number of channels, and several ion channel ated a similar rundown in current, while the Ht31 peptide phosphorylation sites have been identified that could effect could be overcome with perfusion of excess PKA potentially have modulatory roles (Catterall, 1991; Levicatalytic subunit. Furthermore, a mutant Ht31 peptide, tan, 1999; Swope et al., 1999). However, elucidating the unable to antagonize RII/AKAP interactions, had no efmechanisms by which these enzymes achieve specificfect on the current. These experiments provided eviity has been challenging. Certain kinases and phosphadence of a role for kinase anchoring in PKA-mediated tases appear to be intimately associated with ion chansynaptic events; however, they did not specifically adnels (Reinhart and Levitan, 1995; Yu et al., 1997). In the dress which anchoring protein performed this role at case of protein kinase A (PKA) and the type-1 phosphasynapses. tase (PP-1), such specificity may be achieved by com-A more recent report from Greengard and colleagues partmentalization of the enzymes with their substrates. suggests that phosphatase targeting may be equally The focus of this minireview is to highlight advances on important in the modulation of AMPA-type glutamate the targeting and functional coupling of PKA, and more receptors (Yan et al., 1999). In an elegant series of biorecently PP-1, with ion channels through association chemical and electrophysiological experiments, Yan et with targeting subunits and anchoring proteins. al.(1999) have demonstrated that the characteristic