Adam

ADAM12 induces actin cytoskeleton and extracellular matrix reorganization during early adipocyte differentiation by regulating β integrin function

Summary
            Differentiation process changes the morphology of cells. ADAMS 12, a disintegrin and metalloprotease, affects the cell morphology in preadipocytes, changing them from flattened, fibroblastic shape to a more rounded shape. Temporal regulation of multiple and interacting signaling events characterize adipogenesis, leading to the expression of adipocyte-specific genes. A cascade of transcription factors is induced that involved the sequential activation of te CCAAT/enhancer-binding proteins and the peroxisome proliferator activated receptor , leading to the activation of several genes, such as those responsible for lipid transport and metabolism. Initially, fibroblastic preadipocytes stop diving and acquire a rounded morphology. The highest levels of ADAM12 mRNA were detected in preadipocytes at the onset of differentiation. This article explains the molecular mechanism of the effects of ADAM12 on adipocyte differentiation using Transient transfections, Nothern blot analysis, Flow cytometry, Triton X-100 extraction, Protein extraction, iRNA and Microinjection et cetera. The author hypothesized that ADAM12 itself could be part of a β1 integrin cell-adhesion complex and that this might influence the adipogenic differentiation pathway. Using the immunostaining method, it is found that ADAM12 was transiently expressed at the cell surface consequently with the reduced activity of β1. According to the Co-immunoprecipitation studies, ADAM12/β1 integrin complexes were formed in preadipocytes. From the retroviral transduction method, overexpression of ADAM12 at the surface of 3T3-L1 preadipocytes led to the degradation of actin stress fibers and formation of cortical network beneath the cell membrane. ADAM12-expressing cells were more prone to apoptosis, which could be prevented by treating the cells with β1...