ARPP-16/ARPP-19: a highly conserved family of cAMP-regulated phosphoproteins.
ARPP-16 and ARPP-19 are closely related cAMP-regulated phosphoproteins that were initially discovered in mammalian brain as in vitro substrates for protein kinase A (PKA). ARPP-16 is enriched in dopamine-responsive medium spiny neurons in the striatum, while ARPP-19 is ubiquitously expressed. ARPP-19 is highly homologous to alpha-endosulfine and database searches allowed the identification of novel related proteins in D. melanogaster, C. elegans, S. mansoni and yeast genomes. Using isoform-specific antibodies, we now show that ARPP-19 is composed of at least two differentially expressed isoforms (termed ARPP-19 and ARPP-19e/endosulfine). All ARPP-16/19 family members contain a conserved consensus site for phosphorylation by PKA (RKPSLVA in mammalian ARPP-16 and ARPP-19), and this site was shown to be efficiently phosphorylated in vitro by PKA. An antibody that specifically recognized the phosphorylated form of ARPP-16/19/19e was used to examine the phosphorylation of ARPP-16/19 family members in intact cells. In striatal slices, the phosphorylation of ARPP-16 was increased in response to activation of D(1)-type dopamine receptors, and decreased in response to activation of D(2)-type dopamine receptors. In non-neuronal cells, ARPP-19 was highly phosphorylated in response to activation of PKA. These results establish that ARPP-16/19 proteins constitute a family of PKA-dependent intracellular messengers that function in all cells. The high levels of ARPP-16 in striatal neurons and its bi-directional regulation by dopamine suggest a specific role in dopamine-dependent signal transduction. The conservation of this protein family through evolution suggests that it subserves an important cellular function that is regulated by PKA.
Dulubova
I
I
Laboratory of Molecular and Cellular Neuroscience, The Rockefeller University, New York 10021, USA.
Horiuchi
A
A
Snyder
G L
GL
Girault
J A
JA
Czernik
A J
AJ
Shao
L
L
Ramabhadran
R
R
Greengard
P
P
Nairn
A C
AC
D000595:Amino Acid Sequence; D000818:Animals; D016466:CHO Cells; D017124:Conserved Sequence / Q000235:genetics; D003342:Corpus Striatum / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D006224:Cricetinae; D000242:Cyclic AMP / Q000378:metabolism* / Q000494:pharmacology; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D005810:Multigene Family; D009928:Organ Specificity; D010750:Phosphoproteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D020033:Protein Isoforms / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D017447:Receptors, Dopamine D1 / Q000819:agonists / Q000378:metabolism; D017448:Receptors, Dopamine D2 / Q000819:agonists / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
D010750:Phosphoproteins; D020033:Protein Isoforms; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; C064322:cyclic AMP-regulated phosphoprotein 16; C064321:cyclic AMP-regulated phosphoprotein 19; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases