Purification and partial amino acid sequence of a 28 kDa cyclophilin-like component of the rat liver sigma receptor.
The sigma (sigma) receptor, a putative non-opioid receptor site which has been suggested to function as a neuromodulator of dopaminergic and NMDA systems, and is found in brain, liver and many other tissues, has been purified > 560-fold from a detergent-solubilized rat liver membrane preparation by affinity chromatography, using an affinity matrix prepared from an oximino derivative of haloperidol. The affinity column selectively retained principal components of M(r) 28 kDa, 40 kDa and 65 kDa that could be eluted from the column with sigma-selective ligands, specifically dextrallorphan and haloperidol. After dialysis and concentration by ultrafiltration, a loss in density of the 65 kDa component and an increase in the 28 kDa and 40 kDa components was observed. A 15 amino acid N-terminal sequence was obtained for the 28 kDa protein which is identical to the N-terminal sequence of the 17 kDa rat cyclophilin A, a cytosolic protein, suggesting that a critical component of the rat liver sigma receptor may be a cyclophilin. These results support the suggestion that sigma receptors are a key link between the central nervous system and the immune system.
Schuster
D I
DI
Department of Chemistry, New York University, NY 10003.
Ehrlich
G K
GK
Murphy
R B
RB
D000591:Amino Acid Isomerases / Q000737:chemistry; D000595:Amino Acid Sequence; D000818:Animals; D002352:Carrier Proteins / Q000737:chemistry; D008099:Liver / Q000737:chemistry*; D008969:Molecular Sequence Data; D019696:Peptidylprolyl Isomerase; D051381:Rats; D017480:Receptors, sigma / Q000737:chemistry*
D002352:Carrier Proteins; D017480:Receptors, sigma; D000591:Amino Acid Isomerases; D019696:Peptidylprolyl Isomerase