Striatin, a calmodulin‐dependent scaffolding protein, directly binds caveolin‐1

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Abstract
Caveolins are scaffolding proteins able to collect on caveolae a large number of signalling proteins bearing a caveolin‐binding motif. The proteins of the striatin family, striatin, SG2NA, and zinedin, are composed of several conserved, collinearly aligned, protein–protein association domains, among which a putative caveolin‐binding domain [Castets et al. (2000) J. Biol. Chem. 275, 19970–19977]. They are associated in part with membranes. These proteins are mainly expressed within neurons and thought to act both as scaffolds and as Ca2+‐dependent signalling proteins [Bartoli et al. (1999) J. Neurobiol. 40, 234–243]. Here, we show that (1) rat brain striatin, SG2NA and zinedin co‐immunoprecipitate with caveolin‐1; (2) all are pulled down by glutathione‐S‐transferase (GST)–caveolin‐1; (3) a fragment of recombinant striatin containing the putative caveolin‐binding domain binds GST–caveolin‐1. Hence, it is likely that the proteins of the striatin family are addressed to membrane microdomains by their binding to caveolin, in accordance with their putative role in membrane trafficking [Baillat et al. (2001) Mol. Biol. Cell 12, 663–673].