The synaptic scaffolding protein Delphilin interacts with monocarboxylate transporter 2

Abstract

Delphilin, which interacts with a glutamate receptor (GluR) delta2-subunit, is a postsynaptic density scaffolding protein at the cerebellar parallel fiber-Purkinje cell synapses. Delphilin specifically interacts with the GluRdelta2 C-terminus via its postsynaptic density-95/discs-large/ZO-1 (PDZ) domain. As a number of PDZ-containing scaffolding proteins bind to several membrane proteins, we expected that Delphilin might also have other binding partners besides GluRdelta2. To search for the link between Delphilin and other binding proteins, we carried out screening among candidate membrane proteins localized in Purkinje cells by surface plasmon resonance analyses. As a result, we found that the C-terminus of the monocarboxylate transporter 2 binds specifically and significantly with Delphilin PDZ and there is a probable existence of GluRdelta2-Delphilin-monocarboxylate transporter 2 complex in synaptic membranes.