Proceedings of the National Academy of Sciences - PNAS, 1992-10, Vol.89 (19), p.8976-8980
1992
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Details
- Autor(en) / Beteiligte
- Titel
- Inositol Polyphosphate Receptor and Clathrin Assembly Protein AP-2 are Related Proteins that Form Potassium-Selective Ion Channels in Planar Lipid Bilayers
- Ist Teil von
- Proceedings of the National Academy of Sciences - PNAS, 1992-10, Vol.89 (19), p.8976-8980
- Ort / Verlag
- Washington, DC: National Academy of Sciences of the United States of America
- Erscheinungsjahr
- 1992
- Quelle
- MEDLINE
- Beschreibungen/Notizen
- We have previously described an inositol polyphosphate receptor (IPxRec), purified from detergent-solubilized bovine cerebellum microsomes, that displays potassium ion channel activity in planar lipid bilayers. We now find that the IPxRec is closely related to clathrin assembly protein AP-2. The IPxRec and AP-2 purified from bovine brain clathrin-coated vesicles share several structural and functional features: (i) similar subunit composition; each has four major polypeptides that have similar mobility (Mrvalues of 111,000, 100,000, 50,000, and 17,000) and relative intensity by SDS/PAGE analysis; (ii) similar size as studied by molecular sieve chromatography (Mr400,000); (iii) identical N-terminal amino acid sequences for the Mr50,000 subunits and Mr111,000/100,000 doublets; (iv) immunoreactivity of the AP-2 Mr111,000/100,000 doublet to polyclonal antibodies affinity purified against the doublet proteins of the IPxRec; (v) display of the in vitro diagnostic feature of assembly proteins-i.e., they induce the assembly of clathrin cages; and (vi) ion channel activity selective for potassium ions with the same unitary conductance when incorporated into planar lipid bilayers. One difference was found. AP-2 channels were not blocked by inositol 1,3,4,5-tetraphosphate as reported for IPxreceptor channels. These studies suggest a possible connection between the IPxsignaling pathways and receptor-mediated endocytosis.
- Sprache
- Englisch
- Identifikatoren
- ISSN: 0027-8424eISSN: 1091-6490DOI: 10.1073/pnas.89.19.8976Titel-ID: cdi_proquest_miscellaneous_73241364
- Format
- –
- Schlagworte
- Adaptor Proteins, Vesicular Transport, Amino Acid Sequence, Amino acids, Animals, Biological and medical sciences, Cattle, Cell receptors, Cell structures and functions, Cellular biology, Cerebellum - physiology, channels, Chromatography, Affinity, Clathrin - physiology, clathrin assembly protein AP-2, Clathrin coated vesicles, Fundamental and applied biological sciences. Psychology, Gels, inositol polyphosphate, Inositols, Ion channels, Ions, Lipid Bilayers, Lipids, Macromolecular Substances, Microsomes - physiology, Miscellaneous, Molecular and cellular biology, Molecular Sequence Data, Molecular Weight, Phosphoproteins - genetics, Phosphoproteins - isolation & purification, Phosphoproteins - physiology, Potassium, Potassium Channels - physiology, Proteins, Receptors, Receptors, Cell Surface - genetics, Receptors, Cell Surface - isolation & purification, Receptors, Cell Surface - metabolism, Receptors, Cytoplasmic and Nuclear, Sequence Homology, Amino Acid, Ungulates