| Clustering and enhanced activity of an inwardly rectifying potassium channel , Kir4 . 1 , by an anchoring protein , PSD 95 / SAP90 . ^^^ An inwardly rectifying potassium channel predominantly expressed in glial cells , Kir4 . 1 / KAB 2 , has a sequence of Ser Asn Val in its carboxyl terminal end , suggesting a possible interaction with an anchoring protein of the PSD 95 family . ^^^ We examined the effects of PSD 95 on the distribution and function of Kir4 . 1 in a mammalian cell line . ^^^ In contrast , when co expressed with PSD 95 , prominent clustering of Kir4 . 1 in the cell membrane occurred . ^^^ Kir4 . 1 was co immunoprecipitated with PSD 95 in the co expressed cells . ^^^ |