(A, B) Immunoblot analysis of SRF protein tissue distribution (A), and quantification with normalization to heat shock protein 90 (HSP90) as internal control (B) in 3-weeks old mice (n=3/lane). (C) SRF protein levels in mesodermal lineage cell lines, C2C12 murine myoblasts, HIB1B brown preadipocyte, 3T3-L1 white preadipocytes and C3H10T1/2 mesenchymal stem cells. (D, E) Dynamic protein expression of SRF signaling components and brown adipogenic differentiation markers (C/EBPα, C/EBPβ, Prdm16) (D), and SRF transcriptional targets involved in cytoskeleton organization (smooth muscle α-actin SMA, vinculin and α-tubulin) along the indicated time course of C3H10T1/2 differentiation induced by brown adipogenic cocktail (E), with Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as internal control. (F) Fluorescence staining of F-actin stress fibers by Alexa 546-conjugated phalloidin and BODIPY 493/503 labeling of lipid droplets before and at day 8 of brown adipogenic differentiation. Arrowheads: Bodipy-stained lipid droplets. Scale bar: 50μm.