Static and dynamic components of renal cortical brush border and basolateral membrane fluidity: Role of cholesterol

Publisher Website
Google Scholar
Abstract
Static polarization and differential polarized phase fluorimetry studies on rat renal cortical brush border (BBM) and basolateral membranes (BLM) were undertaken to determine the membrane components responsible for differences in BBM and BLM fluidity, whether these differences were due to the order or dynamic components of membrane fluidity and if a fluidity gradient existed within the bilayer. Surface membrane proteins rigidified both BBM and BLM fluidity. Neutral lipid extraction, on the other hand, caused a larger decrease in BBM than BLM fluorescence polarization (0.104vs. 0.60,Pr α) (0.212vs. 0.154,P<0.01) differed markedly between the two membrane fractions. The two membrane components also differed with respect to 2 and 12-anthroyloxy stearate (2-AS, 12-AS) probes, indicating a difference in the dynamic component of membrane fluidity may also be present. DPH and 12-As probes were also used to quantitate inner core membrane fluidity and showed the BBM was less fluid than the BLM for intact membranes, total lipid extracts and phospholipids. Results obtained using the surface membrane probes trimethylammonium-DPH (TMA-DPH) and 2-AS suggested a fluidity gradient existed in both BBM and BLM bilayers with the inner core being more fluid in both membranes. These data indicate cholesterol is in large part responsible for fluidity differences between BBM and BLM and that these membranes, while clearly differing in the order component of membrane fluidity, may also difer in the dynamic component as well.

This publication has 39 references indexed in Scilit: