Alteration of lipids, G proteins, and PKC in cell membranes of elderly hypertensives.
In this study, we quantified the levels of lipids and signaling proteins in erythrocyte membranes from elderly normotensive and hypertensive subjects. In hypertensive subjects, the cholesterol/phospholipid ratio increased significantly in erythrocyte membranes, owing to the reduction of phospholipid levels concomitant with a rise in the levels of cholesterol. In addition, differences were also found in the amount of fatty acids in both phospholipid and cholesterol esters. Erythrocyte membranes from hypertensive subjects contained higher levels of monounsaturated and lower levels of polyunsaturated fatty acids. On the other hand, signaling proteins such as G proteins and protein kinase C have been implicated in the control of blood pressure. Previous studies have shown that the cellular localization and the activity of these proteins are modulated by the type and the abundance of membrane lipids. For this reason, we assessed the levels of these signaling molecules in the membrane. We found that the levels of membrane-associated (active/preactive) G proteins (Galpha(i), Galpha(o), and Gbeta) and protein kinase C were significantly reduced in hypertensive subjects. We believe that these alterations could be related to the etiopathology of hypertension in elderly subjects or alternatively may correspond to adaptive compensatory mechanisms.
Escribá
Pablo V
PV
Laboratory of Molecular and Cellular Biomedicine, Department of Biology, University of the Balearic Islands, Palma de Mallorca, Spain. pablo.escriba@uib.es
Sánchez-Dominguez
José M
JM
Alemany
Regina
R
Perona
Javier S
JS
Ruiz-Gutiérrez
Valentina
V
D000368:Aged; D000369:Aged, 80 and over; D004910:Erythrocyte Membrane / Q000737:chemistry* / Q000201:enzymology; D005260:Female; D020962:Heterotrimeric GTP-Binding Proteins / Q000032:analysis*; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000201:enzymology / Q000378:metabolism*; D007527:Isoenzymes / Q000032:analysis; D008074:Lipoproteins / Q000097:blood; D008297:Male; D008563:Membrane Lipids / Q000032:analysis*; D011493:Protein Kinase C / Q000032:analysis*; D051571:Protein Kinase C-alpha; D021122:Protein Subunits
D007527:Isoenzymes; D008074:Lipoproteins; D008563:Membrane Lipids; D021122:Protein Subunits; C496628:PRKCA protein, human; D011493:Protein Kinase C; D051571:Protein Kinase C-alpha; D020962:Heterotrimeric GTP-Binding Proteins