scholarly journals Characterization of lipoprotein lipase storage vesicles in 3T3-L1 adipocytes

2021 ◽  
Author(s):  
Benjamin Roberts ◽  
Chelsea Yang ◽  
Saskia Neher
Keyword(s):  
Lipoprotein Lipase ◽  
Intracellular Localization ◽  
Calcium Ionophore ◽  
Very Low Density Lipoproteins ◽  
Storage Vesicles ◽  
Muscle Tissues ◽  
Insulin Dependent ◽  
Regulated Trafficking ◽  
Adp Ribosylation Factor

Lipoprotein lipase (LPL) is a secreted triglyceride lipase involved in the clearance of very-low-density lipoproteins and chylomicrons from circulation. LPL is expressed primarily in adipose and muscle tissues and transported to the capillary lumen. LPL secretion is regulated by insulin in adipose tissue, however few studies have examined the regulatory and trafficking steps involved in secretion. Here we describe the intracellular localization and insulin-dependent trafficking of LPL in 3T3-L1 adipocytes. We compared LPL trafficking to the better characterized trafficking pathways taken by leptin and GLUT4. We show that LPL trafficking shares some characteristics of these other pathways, but that LPL subcellular localization and trafficking are distinct from GLUT4 and leptin. LPL secretion occurs slowly in response to insulin and rapidly in response to the calcium ionophore ionomycin. This regulated trafficking is dependent on Golgi protein kinase D and the ADP-ribosylation factor GTPase ARF1 localized to caveolar membrane domains. Together, these data give support to a new trafficking pathway for soluble cargo active in adipocytes.

scholarly journals The characterization of lipoprotein lipase isolated from the post-heparin plasma of the rainbow trout, Salmo gairdneri Richardson

1982 ◽  
Vol 203 (3) ◽  
pp. 727-734 ◽  
Author(s):  
E R Skinner ◽  
A M Youssef
Keyword(s):  
Lipoprotein Lipase ◽  
Specific Activity ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Salmo Gairdneri ◽  
High Density Lipoproteins ◽  
Very Low Density Lipoproteins ◽  
Protamine Sulphate ◽  
Heparin Plasma

1. Intravenous injection of heparin into the trout resulted in the appearance in the plasma of a lipase with the properties of lipoprotein lipase. 2. The enzyme was purified to apparent electrophoretic homogeneity by means of heparin-Sepharose affinity chromatography. The enzyme was eluted with 1.5 M-NaCl and had a specific activity approx. 450-fold that of the post-heparin plasma. 3. The activity of the purified enzyme was inhibited by 1.0 M-NaCl and protamine sulphate and was stimulated between 3- and 8.8-fold by the addition of trout plasma. 4. The activity was strongly stimulated by trout very low density lipoproteins and to a lesser extent by high density lipoproteins. 5. The isolated enzyme fraction gave a single band on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and had an apparent subunit M4 of 63 000. 6. These results suggest that the uptake of lipid by the tissues in the trout can occur by a process similar to that in mammals.

The Immuno-Electron Microscopic Localization of the Mo-Fe Protein Component of Nitrogenase in Cells of Azotobacter Vinelandii

1973 ◽  
Vol 31 ◽  
pp. 574-575
Author(s):  
J. T. Stasny ◽  
R. C. Burns ◽  
R. W. F. Hardy
Keyword(s):  
Cellular Localization ◽  
Direct Evidence ◽  
Azotobacter Vinelandii ◽  
Intracellular Localization ◽  
Protein Component ◽  
Electron Microscopic ◽  
Thin Sections ◽  
Fe Protein ◽  
Intracytoplasmic Membranes

Structure-functlon studies of biological N2-fixation have correlated the presence of the enzyme nitrogenase with increased numbers of intracytoplasmic membranes in Azotobacter. However no direct evidence has been provided for the internal cellular localization of any nitrogenase. Recent advances concerned with the crystallizatiorTand the electron microscopic characterization of the Mo-Fe protein component of Azotobacter nitrogenase, prompted the use of this purified protein to obtain antibodies (Ab) to be conjugated to electron dense markers for the intracellular localization of the protein by electron microscopy. The present study describes the use of ferritin conjugated to goat antitMo-Fe protein immunoglobulin (IgG) and the observations following its topical application to thin sections of N2-grown Azotobacter.

1672-P: Characterization of Immune Checkpoint Inhibitor–Mediated Hyperglycemia: Beyond Insulin-Dependent Diabetes

Diabetes ◽  
2020 ◽  
Vol 69 (Supplement 1) ◽  
pp. 1672-P
Author(s):  
AMANDA LEITER ◽  
EMILY CARROLL ◽  
DANIELLE C. BROOKS ◽  
JENNIFER BEN SHIMOL ◽  
ELLIOT EISENBERG ◽  
...  
Keyword(s):  
Immune Checkpoint ◽  
Immune Checkpoint Inhibitor ◽  
Checkpoint Inhibitor ◽  
Insulin Dependent Diabetes ◽  
Insulin Dependent

scholarly journals Characterization of a glucose-repressible ADP-ribosylation factor 3 (ARF3) from Saccharomyces cerevisiae.

1994 ◽  
Vol 269 (33) ◽  
pp. 20931-20937
Author(s):  
F.J. Lee ◽  
L.A. Stevens ◽  
Y.L. Kao ◽  
J. Moss ◽  
M. Vaughan
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Adp Ribosylation ◽  
Adp Ribosylation Factor
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