Tani, TaneliMercurio, Arthur M.2022-08-232022-08-232001-08-022010-11-12J Biol Chem. 2001 Sep 28;276(39):36535-42. Epub 2001 Jul 30. <a href="http://dx.doi.org/10.1074/jbc.M105785200">Link to article on publisher's site</a>0021-9258 (Linking)10.1074/jbc.M10578520011479315https://hdl.handle.net/20.500.14038/26285We used published peptide library data to identify PDZ recognition sequences in integrin alpha subunit cytoplasmic domains and found that the alpha(6)A and alpha(5) subunits contain a type I PDZ binding site (TSDA*) (asterisk indicates the stop codon). The alpha(6)A cytoplasmic domain was used for screening a two-hybrid library to find interacting proteins. The bulk of the captured cDNAs (60%) coded for TIP-2/GIPC, a cytoplasmic protein with one PDZ domain. The interaction of TIP-2/GIPC with different integrin subunits was tested in two-hybrid and in vitro binding assays. Surprisingly, TIP-2/GIPC bound strongly to the C terminus of both alpha(6)A and alpha(6)B, although the alpha(6)B sequence (ESYS*) is not suggestive of a PDZ binding site because of its polar C-terminal residue. For high affinity interaction with TIP-2/GIPC, at least one of the residues at positions -1 and -3 must be negatively charged. An aliphatic residue at position 0 increases the affinity of but is not required for this interaction. The alpha(5) integrin subunit also bound to TIP-2/GIPC. The alpha(6) integrin and TIP-2/GIPC co-localize in retraction fibers in carcinoma cells plated on laminin, a finding suggesting a functional interaction in vivo. Our results demonstrate that both splice variants of alpha(6) integrin contain a conserved PDZ binding site that enables interaction with TIP-2/GIPC. The binding site in alpha(6)B defines a new subclass of type I PDZ interaction site, characterized by a non-aliphatic residue at position 0.en-USAdaptor Proteins, Signal TransducingAlternative SplicingAmino Acid SequenceAntigens, CDBinding SitesBlotting, NorthernCarrier ProteinsCell AdhesionCells, CulturedGlutathione TransferaseHumansIntegrin alpha5Integrin alpha6Molecular Sequence DataNeuropeptidesPeptide LibraryPlasmidsPoint MutationProtein BindingProtein Structure, TertiaryRNA, MessengerRecombinant ProteinsSequence Homology, Amino AcidTumor Cells, CulturedTwo-Hybrid System TechniquesCancer BiologyNeoplasmsJournal Articlehttps://escholarship.umassmed.edu/cancerbiology_pp/2011640424cancerbiology_pp/201