Figure 4. Mitochondrial β-oxidation alters plasma membrane lipids and signaling.

(a) Ex vivo epidermal fatty acid dependent respiration, fatty acid independent respiration and total respiration measured by oxygen consumption in the presence or absence of Etomoxir (Eto) treatment. Fatty acid dependent respiration was defined as the difference between total respiration and Eto inhibited (fatty acid independent) respiration. Error bars represent means+/−s.e.m., (WT FVB n=10, K5-UCP3 n=8). *Indicates significantly different from wild-type FVB, same treatment (P<0.05, Student's t-test). (b) Immunoblot for sub-cellular localization of Akt and PTEN in membrane and cytoplasmic fractions from wild-type FVB and K5-UCP3 epidermis topically treated with 2.5 μg TPA or acetone. α-3 integrin and β-actin were used as controls to verify membrane and cytoplasmic fractions, respectively. (c) Relative quantification of Akt in cytoplasmic and membrane fractions from triplicate separate immunoblotting experiments via densitometry. Cytoplasmic and membrane fractions were normalized to β-actin and α3-integrin, respectively. Data represent means+/−s.e.m. (n=3 biological replicates). *Indicates significantly different from wild-type FVB, same treatment (P<0.05, Student's t-test). (d) Immunoblot for Akt Ser 473 phosphorylation in wild-type FVB and K5-UCP3 epidermal lysates 6 h following topical treatment with 1-mg Eto ethyl ester or ethyl acetate (EA, vehicle control). Immunoblotting for β-Actin was used to confirm equal loading.