Department of Anesthesiology

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ARPP-21, a cyclic AMP-regulated phosphoprotein enriched in dopamine-innervated brain regions. I. Amino acid sequence of ARPP-21B from bovine caudate nucleus.

TitleARPP-21, a cyclic AMP-regulated phosphoprotein enriched in dopamine-innervated brain regions. I. Amino acid sequence of ARPP-21B from bovine caudate nucleus.
Publication TypeJournal Article
Year of Publication1989
AuthorsWilliams KR, Hemmings HC, LoPresti MB, Greengard P
JournalJ Neurosci
Volume9
Issue10
Pagination3631-7
Date Published1989 Oct
ISSN0270-6474
KeywordsAmino Acid Sequence, Animals, Brain, Cattle, Caudate Nucleus, Chromatography, High Pressure Liquid, Chymotrypsin, Cyclic AMP, Dopamine, Endopeptidases, Metalloendopeptidases, Molecular Sequence Data, Phosphoproteins, Subtilisins, Trypsin
Abstract

ARPP-21 (cAMP-regulated phosphoprotein, Mr = 21,000 as determined by SDS-PAGE) is a major cytosolic substrate for cAMP-stimulated protein phosphorylation in dopamine-innervated regions of the rat CNS. It has recently been purified to homogeneity from bovine caudate nucleus and characterized (Hemmings and Greengard, 1989). ARPP-21 is isolated as 2 isoforms, ARPP-21A and ARPP-21B. The amino acid sequence of purified bovine ARPP-21B has now been determined by gas-phase sequencing. The S-14C-carboxymethylated protein was subjected to enzymatic cleavage with trypsin, chymotrypsin, subtilisin, and endoproteinase Lys-C. The resulting peptides were purified by high-performance liquid chromatography, and selected peptides were subjected to amino acid analysis and/or amino acid sequencing by automated Edman degradation. ARPP-21B consists of a single NH2-terminal blocked polypeptide chain of 88 residues, with a calculated molecular mass of 9561 Da, including an NH2-terminal acetyl group inferred by deblocking with an acylaminopeptidase. This molecular mass is significantly lower than earlier estimates based on SDS-PAGE or hydrodynamic measurements. The seryl residue phosphorylated by cAMP-dependent protein kinase (Hemmings et al., 1989) is located at position 55. The molecule contains 1 cysteinyl residue, at position 71, and contains no methionyl, tyrosyl, phenylalanyl, tryptophanyl, or histidinyl residues. Determination of the primary structure of ARPP-21, one of several phosphoproteins localized to dopaminoceptive neurons in the basal ganglia, provides a framework for further investigations into the molecular mechanisms involved in dopaminergic neurotransmission.

Alternate JournalJ. Neurosci.
PubMed ID2552036
Grant ListGM-31539 / GM / NIGMS NIH HHS / United States
MH-40899 / MH / NIMH NIH HHS / United States