*2.7. UDCA-LPE Mediates the Compartmentalization of Integrins into Lipid Rafts*

Cell lysates were subjected to lipid fractionation and the levels of various integrins in 12 fractions were analysed by western blotting. A marker for lipid rafts caveolin-1 was mostly detected in fractions 2–4 of control CL48 cell lysates and in fractions 1–4 in cells treated with UDCA-LPE for 30 min (Figure 7A). This indicated that the integrity of lipid rafts was not disturbed by UDCA-LPE and that lipid rafts were maintained in lower density fractions 1–4. UDCA-LPE treatment did not alter SRC protein concentrations in any of lipid fractions (Figure 7H) but markedly increased concentrations of integrin α2, α3, α5, αv, β1 and β4 in lipid-raft fractions 1–4 concomitant with decreased concentrations in fractions 5–8 (Figure 7B–G). Moreover, co-incubation with GRGDSP inhibited UDCA-LPE-induced translocation of these integrins to lipid-raft fractions (Figure 7B–G).

**Figure 7.** UDCA-LPE mediates compartmentalization of integrins into lipid rafts. (**A**–**C**) Lipid fractionation of CL48 cells after treatment with 200 μg/mL RGD-containing peptide GRGDSP for 1 h and 90 μM UDCA-LPE for 30 min. Separated fractions were immunoblotted with antibodies against (**A**) caveolin-1, (**B**) integrin α2, (**C**) integrin α3, (**D**) integrin α5, (**E**) integrin αv, (**F**) integrin β1, (**G**) integrin β4 or (**H**) SRC respectively. The protein of interest was normalized to the amount of all proteins in 12 fractions as 100%. Data are means ± the standard deviation of three independent experiments. \*\*\* *p* < 0.001, \*\* *p* < 0.01, \* *p* < 0.05.
