Channel-interacting PDZ protein, 'CIPP', interacts with proteins involved in cytoskeletal dynamics.
Neuronal CIPP (channel-interacting PDZ protein) is a multivalent PDZ protein that interacts with specific channels and receptors highly expressed in the brain. It is composed of four PDZ domains that behave as a scaffold to clusterize functionally connected proteins. In the present study, we selected a set of potential CIPP interactors that are involved directly or indirectly in mechanisms of cytoskeletal remodelling and membrane protrusion formation. For some of these, we first proved the direct binding to specific CIPP PDZ domains considered as autonomous elements, and then confirmed the interaction with the whole protein. In particular, the small G-protein effector IRSp53 (insulin receptor tyrosine kinase substrate protein p53) specifically interacts with the second PDZ domain of CIPP and, when co-transfected in cultured mammalian cells with a tagged full-length CIPP, it induces a marked reorganization of CIPP cytoplasmic localization. Large punctate structures are generated as a consequence of CIPP binding to the IRSp53 C-terminus. Analysis of the puncta nature, using various endocytic markers, revealed that they are not related to cytoplasmic vesicles, but rather represent multi-protein assemblies, where CIPP can tether other potential interactors.
Alpi
Emanuele
E
Cell and Developmental Biology Laboratory, Department of Biology, University of Pisa, 56010 Pisa, Italy.
Landi
Elena
E
Barilari
Manuela
M
Serresi
Michela
M
Salvadori
Piero
P
Bachi
Angela
A
Dente
Luciana
L
D000818:Animals; D015153:Blotting, Western; D001921:Brain / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D002846:Chromatography, Affinity; D003599:Cytoskeleton / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism; D006801:Humans; D047468:Immunoprecipitation; D051379:Mice; D008856:Microscopy, Fluorescence; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000502:physiology; D011485:Protein Binding; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
C119539:BAIAP2 protein, human; D002352:Carrier Proteins; C113147:Cipp protein, mouse; D009419:Nerve Tissue Proteins