Abstract
The GTP-binding proteins are well-known regulators of cellular functions, including vesicular transport. Cholera toxin, which is known to catalyse ADP-ribosylation of the alpha s subunit of heterotrimeric G proteins, stimulates secretory vesicle formation from the trans-Golgi network. Here we describe a new cholera toxin target, an 'extra large' G protein (XL alpha s; M(r) 92K) which consists of a new 51K XL-portion linked to a G alpha s truncated at the amino terminus. XL alpha s is specifically associated with the trans-Golgi network and occurs selectively in cells containing both the regulated and the constitutive pathway of protein secretion. Hence, XL alpha s may mediate the effects of cholera toxin on secretory vesicle formation.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adenosine Diphosphate Ribose / metabolism
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Amino Acid Sequence
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Animals
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Base Sequence
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Cholera Toxin / pharmacology
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Chromogranins
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DNA, Complementary
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GTP-Binding Protein alpha Subunits, Gs*
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GTP-Binding Proteins / drug effects
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GTP-Binding Proteins / genetics
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GTP-Binding Proteins / metabolism*
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Golgi Apparatus / metabolism
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Heterotrimeric GTP-Binding Proteins*
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Membrane Proteins / metabolism
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Molecular Sequence Data
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Nerve Tissue Proteins*
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PC12 Cells
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Rats
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Subcellular Fractions
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Tissue Distribution
Substances
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Chromogranins
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DNA, Complementary
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Membrane Proteins
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Nerve Tissue Proteins
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Adenosine Diphosphate Ribose
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Cholera Toxin
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GTP-Binding Proteins
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Gnas protein, rat
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GTP-Binding Protein alpha Subunits, Gs
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Heterotrimeric GTP-Binding Proteins