2D-PAGE analysis: adrenergically regulated pineal protein AIP 37/6 is a phosphorylated isoform of cytosolic malate dehydrogenase.
The adrenergic transmitter norepinephrine (NE) dramatically increases the prominence of only two out of the hundreds of [35S]methionine-labeled pineal proteins resolved by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). One of these regulated proteins is AIP 37/6 (37 kDa, pI approximately 6). The labeling of this protein is increased approximately 100-fold by NE. In the study presented here the identity of AIP 37/6 was investigated. The results of microsequencing, immunochemical analysis of 2D-PAGE blots and size exclusion chromatography indicate that AIP 37/6 is an isoform of cytosolic malate dehydrogenase (cMDH; approximately 36.3 kDa; pI approximately 6.5). Associated studies indicate that this isoform is phosphorylated whereas the bulk of cMDH is not. Cotranslational phosphorylation of cMDH is discussed.
Weller
J L
JL
Section of Neuroendocrinology, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
Jaffe
H
H
Roseboom
P H
PH
Zylka
M J
MJ
Klein
D C
DC
D000818:Animals; D001345:Autoradiography; D003513:Cycloheximide / Q000494:pharmacology; D005260:Female; D007150:Immunohistochemistry; D008291:Malate Dehydrogenase / Q000378:metabolism*; D008297:Male; D008715:Methionine / Q000494:pharmacology; D010766:Phosphorylation; D010870:Pineal Gland / Q000378:metabolism* / Q000502:physiology*; D011506:Proteins / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
D011506:Proteins; D003513:Cycloheximide; D008715:Methionine; D008291:Malate Dehydrogenase