Supplemental Material

This article contains the following supporting material:

• Figure 1 - Nearly the entire open reading frame of TIP-1 consists of a single PDZ domain that is highly conserved across species. Identities are boxed, while a bold line indicates the residues involved in the PDZ domain. A BLAST search of the protein databases revealed orthologous proteins in Canis Familiaris (dog), Mus musculus (mouse), Gus gallus (chicken), Xenopus tropicalis (frog), Danio rerio (zebrafish), Drosophila melanogaster (fly) and Caenorhabditis elegans (worm) (Supplemental Figure I), suggesting that TIP-1 may have an evolutionarily conserved function. Since other PDZ proteins rely on multiple protein-protein interaction domains to effectively couple different binding partners, TIP-1 represents a dramatic a departure from the PDZ protein scaffolding scheme.

• Figure 2 - Anti-TIP-1 antibody specifically recognized the predicted 16 kDa band for epitope-tagged TIP-1 in lysates from cells over expressing myc-TIP-1, but not in cells transfected with HA-mLin-7, an unrelated PDZ protein (left). Anti-myc antibodies detected the same band (center). To control for expression, lysates from HA-mLin-7-transfected cells were immunoblotted with an anti-HA antibody (right).