Cloning, characterization, and functional studies of a human 40-kDa catecholamine-regulated protein: implications in central nervous system disorders.
Catecholamine-regulated proteins (CRPs) have been shown to bind dopamine and other structurally related catecholamines; in particular, the 40-kDa CRP (CRP40) protein has been previously cloned and functionally characterized. To determine putative human homologs, BLAST analysis using the bovine CRP40 sequence identified a human established sequence tag (EST) with significant homology (accession #BQ224193). Using this EST, we cloned a recombinant human brain CRP40-like protein, which possessed chaperone activity. Radiolabeled dopamine binding studies with recombinant human CRP40 protein demonstrated the ability of this protein to bind dopamine with low affinity and high capacity. The full-length human CRP40 nucleotide sequence was elucidated (accession #DQ480334) with RNA ligase-mediated rapid amplification of complementary DNA ends polymerase chain reaction, while Northern blot hybridization suggested that human CRP40 is an alternative splice variant of the 70-kDa mitochondrial heat shock protein, mortalin. Human SH-SY5Y neuroblastoma cells treated with the antipsychotic drug, haloperidol, exhibited a significant increase in CRP40 messenger RNA expression compared to untreated control cells, while other dopamine agonists/antagonists also altered CRP40 expression and immunolocalization. In conclusion, these results show that we have cloned a splice variant of mortalin with a novel catecholamine binding function and that this chaperone-like protein may be neuroprotective in dopamine-related central nervous system disorders.
Gabriele
Joseph
J
Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, ON, Canada. gabriejp@mcmaster.ca
Pontoriero
Giuseppe F
GF
Thomas
Nancy
N
Thomson
Christy A
CA
Skoblenick
Kevin
K
Pristupa
Zdenek B
ZB
Mishra
Ram K
RK
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002417:Cattle; D045744:Cell Line, Tumor; D002493:Central Nervous System Diseases / Q000378:metabolism; D003001:Cloning, Molecular; D004298:Dopamine / Q000378:metabolism*; D018840:HSP70 Heat-Shock Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D006220:Haloperidol / Q000378:metabolism; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D009474:Neurons / Q000378:metabolism*; D012326:RNA Splicing; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012689:Sequence Homology, Nucleic Acid
D018840:HSP70 Heat-Shock Proteins; D009419:Nerve Tissue Proteins; D011994:Recombinant Proteins; C422207:catecholamine-regulated protein, 40 kDa; C080352:mortalin; D006220:Haloperidol; D004298:Dopamine