scholarly journals Subcellular localization of sterol carrier protein-2 in rat hepatocytes: its primary localization to peroxisomes.

1989 ◽  
Vol 108 (4) ◽  
pp. 1353-1361 ◽  
Author(s):  
G A Keller ◽  
T J Scallen ◽  
D Clarke ◽  
P A Maher ◽  
S K Krisans ◽  
...  
Keyword(s):  
Subcellular Localization ◽  
Rat Liver ◽  
Polyclonal Antibodies ◽  
Rat Hepatocytes ◽  
Carrier Protein ◽  
Sterol Carrier Protein ◽  
Rat Liver Cells ◽  
Ultrathin Frozen Sections ◽  
Sterol Carrier Protein 2

Sterol carrier protein-2 (SCP-2) is a nonenzymatic protein of 13.5 kD which has been shown in in vitro experiments to be required for several stages in cholesterol utilization and biosynthesis. The subcellular localization of SCP-2 has not been definitively established. Using affinity-purified rabbit polyclonal antibodies against electrophoretically pure SCP-2 from rat liver, we demonstrate by immunoelectron microscopic labeling of ultrathin frozen sections of rat liver that the largest concentration of SCP-2 is inside peroxisomes. In addition the immunolabeling indicates that there are significant concentrations of SCP-2 inside mitochondria, and associated with the endoplasmic reticulum and the cytosol, but not inside the Golgi apparatus, lysosomes, or the nucleus. These results were confirmed by immunoblotting experiments with proteins from purified subcellular fractions of the rat liver cells carried out with the anti-SCP-2 antibodies. The large concentration of SCP-2 inside peroxisomes strongly supports the proposal that peroxisomes are critical sites of cholesterol utilization and biosynthesis. The presence of SCP-2 inside peroxisomes and mitochondria raises questions about the mechanisms involved in the differential targeting of SCP-2 to these organelles.

Isolation and Characterization of 26- and 30-kDa Rat Liver Proteins Immunoreactive to Anti-Sterol Carrier Protein-2 Antibodies

1998 ◽  
Vol 13 (3) ◽  
pp. 337-348 ◽  
Author(s):  
Lixia Pu ◽  
William B. Foxworth ◽  
Ann B. Kier ◽  
Roland S. Annan ◽  
Steven A. Carr ◽  
...  
Keyword(s):  
Rat Liver ◽  
Carrier Protein ◽  
Sterol Carrier Protein ◽  
Isolation And Characterization ◽  
Sterol Carrier Protein 2

Crystallization and initial X-ray analysis of rabbit mature sterol carrier protein 2

1999 ◽  
Vol 55 (8) ◽  
pp. 1478-1480
Author(s):  
Thomas Choinowski ◽  
James H. Dyer ◽  
Bernhard Maderegger ◽  
Kaspar H. Winterhalter ◽  
Helmut Hauser ◽  
...  
Keyword(s):  
Carrier Protein ◽  
Sterol Carrier Protein ◽  
Asymmetric Unit ◽  
Intracellular Protein ◽  
Hanging Drop ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Sterol Carrier Protein 2

Sterol carrier protein 2 (SCP2) is a basic intracellular protein which facilitates the in vitro intermembrane transfer of cholesterol, phospholipids and glycolipids. SCP2 was expressed in Escherichia coli, purified to apparent electrophoretic homogeneity and crystallized. Single crystals were obtained by hanging-drop vapour diffusion using ammonium sulfate as precipitant. These crystals belong to space group P41212 or its enantiomorph, with unit-cell parameters a = b = 57.5, c = 86.5 Å, and have one molecule in the crystallographic asymmetric unit. Intensity data to 1.8 Å resolution were collected from native SCP2 crystals using synchrotron radiation, were processed and scaled with an R linear = 4.9%.

scholarly journals Primary sequence and structural analysis of sterol carrier protein 2 from rat liver: homology with immunoglobulins.

1987 ◽  
Vol 262 (27) ◽  
pp. 13219-13227 ◽  
Author(s):  
A Pastuszyn ◽  
B J Noland ◽  
J F Bazan ◽  
R J Fletterick ◽  
T J Scallen
Keyword(s):  
Structural Analysis ◽  
Rat Liver ◽  
Carrier Protein ◽  
Sterol Carrier Protein ◽  
Primary Sequence ◽  
Sterol Carrier Protein 2

Expression of sterol carrier protein 2 (SCP2) in human adrenocortical tissue

1996 ◽  
Vol 134 (4) ◽  
pp. 501-507 ◽  
Author(s):  
Toshihiko Yanase ◽  
Takayuki Hara ◽  
Yoshiyuki Sakai ◽  
Ryoichi Takayanagi ◽  
Hajime Nawata
Keyword(s):  
Free Cholesterol ◽  
In Vitro Studies ◽  
Carrier Protein ◽  
Northern Blot Hybridization ◽  
Sterol Carrier Protein ◽  
Adrenocortical Adenomas ◽  
Adrenocortical Carcinomas ◽  
Tissue Specimens ◽  
Sterol Carrier Protein 2

Yanase T, Hara T, Sakai Y, Takayanagi R, Nawata H. Expression of sterol carrier protein 2 (SCP2) in human adrenocortical tissue. Eur J Endocrinol 1996;134:501–7. ISSN 0804–4643 Sterol carrier protein 2 (SCP2) has been implicated in adrenal steroidogenesis by in vitro studies. In order to clarify the clinical significance of SCP2 in human steroidogenesis, we investigated the expression of SCP2 mRNA in various types of adrenocortical tissue and one testis and examined the correlation between the amounts of SCP2 and other values such as the free cholesterol content and the cholesterol side-chain cleavage (SCC) activity in the tissue mitochondria, The types of adrenocortical tissue examined included adrenocortical carcinomas (N = 3), adrenocortical adenomas from patients with Conn's syndrome (N = 3) and from patients with Cushing's syndrome (N = 3), non-functioning adrenocortical adenomas (N = 2) and normal adrenal glands (N = 2). Northern blot hybridization predominantly revealed a 1.8-kb SCP2 mRNA in all tissue specimens examined. The mRNA concentrations of SCP2 in two out of three adrenocortical carcinomas were relatively lower than those in other types of tissue. No other special tendency was observed regarding the mRNA expression levels in various tissue specimens. The mRNA concentrations of SCP2 correlated significantly with mitochondrial contents of free cholesterol (r = 0.67, p < 0.01), but was not correlated with the SCC activities in mitochondria measured by an in vitro enzyme assay. The mitochondrial SCC activities, however, were correlated significantly with the protein levels of mitochondrial P-450 scc determined by a Western blot analysis (r = 0.79, p < 0.01). The significant positive correlation between mRNA concentrations of SCP2 and the mitochondrial content of free cholesterol suggests that the central role of SCP2 in human steroidogenic tissues may be in part a translocation of cytoplasmic free cholesterol to the mitochondria, as demonstrated previously by in vitro studies. Toshihiko Yanase, Third Department of Internal Medicine, Faculty of Medicine, Maidashi 3-1-1, Higashi-ku, Fukuoka 812, Japan

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