StAR PROTEIN AND THE REGULATION OF STEROID HORMONE BIOSYNTHESISSteroid hormone biosynthesis is acutely regulated by pituitary trophic hormones and other steroidogenic stimuli. This regulation requires the synthesis of a protein whose function is to translocate cholesterol from the outer to the inner mitochondrial membrane in steroidogenic cells, the rate-limiting step in steroid hormone formation. The steroidogenic acute regulatory StAR protein is an indispensable component in star protein and the regulation of steroid hormone biosynthesis process and is the best candidate to fill the role of the putative regulator. StAR is expressed in steroidogenic tissues in response to agents that stimulate steroid production, and mutations in the StAR gene result in the disease congenital lipoid adrenal hyperplasia, reuglation which steroid hormone biosynthesis is severely stag. The StAR null mouse has a phenotype that is essentially identical to the human radsteroids desinstalar.
StAR protein and the regulation of steroid hormone biosynthesis. - PubMed - NCBI
Two short-lived precursor proteins, pp37 and pp32, of the mitochondrial phosphoprotein pp30 formerly denoted as ib have been detected in Bt2cAMP-stimulated rat adrenal cortex cells, incubated at 25 degrees C or with 1,ortho-phenanthroline at 37 degrees C. Subsequently, these two precursor proteins were also identified in cells incubated at 37 degrees C, where they are present only at low levels due to their short half-life.
As for pp30, inhibition of cytosolic translation prevents the production of pp37 and pp The larger precursor protein pp37 has an apparent molecular mass of 37 kDa, an isoelectric point of approximately 7.
Pulse-chase studies indicate that this protein is processed into the smaller protein, pp32, which has an apparent molecular mass of 32 kDa, an isoelectric point of approximately 6. This latter protein is the immediate precursor of pp Since ortho-phenanthroline inhibits the mitochondrial processing protease, while the lower incubation temperature slows both protein import and protease processing, the experimental conditions necessary to detect these proteins are consistent with pp37 being a precursor protein that contains two cleavable presequences and is imported into the mitochondrion.
The sequential removal of these sequences produces the mature protein pp You'll be in good company. Journal of Lipid Research. Regulation of steroid hormone biosynthesis. Identification of precursors of a phosphoprotein targeted to the mitochondrion in stimulated rat adrenal cortex cells.
Abstract Two short-lived precursor proteins, pp37 and pp32, of the mitochondrial phosphoprotein pp30 formerly denoted as ib have been detected in Bt2cAMP-stimulated rat adrenal cortex cells, incubated at 25 degrees C or with 1,ortho-phenanthroline at 37 degrees C. Prev Next Table of Contents. Services Email this article to a friend Alert me when this article is cited Alert me if a correction is posted Alert me when eletters are published Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Download to citation manager Request Permissions.
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