The membrane proximal region of the integrin beta cytoplasmic domain can mediate oligomerization.
Integrin-ligand binding generates many intracellular signals, including signals to initiate focal contact formation and to regulate cellular decisions concerning growth and differentiation. Oligomerization of the beta subunit cytoplasmic domain appears to be required for many of these events. In order to study these processes, we have generated a novel chimeric protein, consisting of the chicken integrin beta 1 cytoplasmic domain connected to the central rod domain of a neuronal intermediate filament, alpha-internexin. This chimeric protein, when expressed transiently in 293T cells, oligomerizes in a beta cytoplasmic domain-dependent manner. This oligomerization requires the membrane proximal amino acids LLMII of the beta 1 cytoplasmic domain, as demonstrated by deletion analysis. Therefore, the integrin beta cytoplasmic domain in this system contains an oligomerization function, which may provide some insight as to the function of intact integrins in vivo.
Zage
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PE
Department of Pathology, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA.
Marcantonio
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EE
D000595:Amino Acid Sequence; D000818:Animals; D002352:Carrier Proteins / Q000032:analysis / Q000235:genetics; D015815:Cell Adhesion Molecules / Q000378:metabolism; D002478:Cells, Cultured; D002645:Chickens; D003593:Cytoplasm / Q000737:chemistry* / Q000201:enzymology; D005353:Fibronectins / Q000032:analysis; D005455:Fluorescent Antibody Technique; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D017353:Gene Deletion; D006801:Humans; D019012:Integrin beta1 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D007381:Intermediate Filament Proteins; D007668:Kidney / Q000166:cytology; D008969:Molecular Sequence Data; D016296:Mutagenesis / Q000502:physiology; D009841:Oligonucleotides / Q000235:genetics; D017434:Protein Structure, Tertiary; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics; D015398:Signal Transduction / Q000502:physiology; D012995:Solubility; D014162:Transfection
D002352:Carrier Proteins; D015815:Cell Adhesion Molecules; D005353:Fibronectins; D019012:Integrin beta1; D007381:Intermediate Filament Proteins; D009841:Oligonucleotides; D011993:Recombinant Fusion Proteins; C046643:alpha-internexin; D011505:Protein-Tyrosine Kinases; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; C496050:PTK2 protein, human; C496052:Ptk2 protein, rat