The PDZ domain of TIP-2/GIPC interacts with the C-terminus of the integrin alpha5 and alpha6 subunits.
Different cDNA libraries were screened by the yeast two-hybrid system using as a bait the cytoplasmic sequence of integrin alpha6A or alpha6B subunits. Surprisingly, the same PDZ domain-containing protein, TIP-2/GIPC, was isolated with either of the variants, although their sequences are different. Direct interaction assays with the cytoplasmic domain of the integrin alpha1--7 subunits revealed that in addition to alpha6A and alpha6B, TIP-2/GIPC reacted also with alpha5, but not other alpha integrin subunits. The specificity of the interaction was confirmed by in vitro protein binding assays with purified peptides corresponding to integrin cytoplasmic domains. Further analysis with either truncation fragments of TIP-2/GIPC or mutated integrin cytoplasmic domains indicated that the interaction occurs between the PDZ domain of TIP-2/GIPC and a consensus PDZ domain-binding sequence, SDA, present at the C-terminus of the integrin alpha5 and alpha6A subunits. The integrin alpha6B subunit terminates with a different sequence, SYS, which may represent a new PDZ domain-binding motif.
El Mourabit
Haquima
H
Institute for Biochemistry II, Medical Faculty, University of Cologne, Joseph-Stelzmann-Str. 52, 50931 Cologne, Germany.
Poinat
Patrice
P
Koster
Jan
J
Sondermann
Holger
H
Wixler
Viktor
V
Wegener
Elmar
E
Laplantine
Emmanuel
E
Geerts
Dirk
D
Georges-Labouesse
Elisabeth
E
Sonnenberg
Arnoud
A
Aumailley
Monique
M
D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D015703:Antigens, CD / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D002352:Carrier Proteins / Q000378:metabolism*; D002460:Cell Line; D003593:Cytoplasm / Q000378:metabolism; D006388:Hemagglutinins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D039482:Integrin alpha5; D039503:Integrin alpha6; D016023:Integrins / Q000235:genetics / Q000378:metabolism*; D009479:Neuropeptides / Q000378:metabolism*; D010455:Peptides / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D020798:Two-Hybrid System Techniques
D048868:Adaptor Proteins, Signal Transducing; D015703:Antigens, CD; D002352:Carrier Proteins; C492009:GIPC1 protein, human; D006388:Hemagglutinins; D039482:Integrin alpha5; D039503:Integrin alpha6; D016023:Integrins; D009479:Neuropeptides; D010455:Peptides