Tissue Factor is a cell-surface glycoprotein expressed in various cells of the vasculature and is the principal regulator of the blood coagulation cascade and hemostasis. Notably, aberrant... Show moreTissue Factor is a cell-surface glycoprotein expressed in various cells of the vasculature and is the principal regulator of the blood coagulation cascade and hemostasis. Notably, aberrant expression of Tissue Factor is associated with cardiovascular pathologies such as atherosclerosis and thrombosis. Here, we sought to identify factors that regulate Tissue Factor gene expression and activity. Tissue Factor gene expression is regulated by various transcription factors, including activating protein-1 and nuclear factor-kappa B. The peptidyl-prolyl isomerase Pin1 is known to modulate the activity of these two transcription factors, and we now show that Pin1 augments Tissue Factor gene expression in both vascular smooth muscle cells and activated endothelial cells via activating protein-1 and nuclear factor-kappa B signaling. Furthermore, the cytoplas-mic domain of Tissue Factor contains a well-conserved phospho-Ser258-Pro259 amino-acid motif recognized by Pin1. Using co-immunoprecipitation and solution nuclear magnetic resonance spectroscopy, we show that the WW-domain of Pin1 directly binds the cytoplasmic domain of Tissue Factor. This interaction occurs via the phospho-Ser258-Pro259 sequence in the Tissue Factor cytoplasmic domain and results in increased protein half-life and pro-coagulant activity. Taken together, our results establish Pin1 as an upstream regulator of Tissue Factor-mediated coagulation, thereby opening up new avenues for research into the use of specific Pin1 inhibitors for the treatment of diseases characterized by pathological coagulation, such as thrombosis and atherosclerosis. Show less
Mutations in genes encoding proteins of the human dystrophin-associated glycoprotein complex (DGC) cause the Duchenne, Becker and limb-girdle muscular dystrophies. Subsets of the DGC proteins form... Show moreMutations in genes encoding proteins of the human dystrophin-associated glycoprotein complex (DGC) cause the Duchenne, Becker and limb-girdle muscular dystrophies. Subsets of the DGC proteins form tissue-specific complexes which are thought to play structural and signaling roles in the muscle and at the neuromuscular junction. Furthermore, mutations in the dystrophin gene that lead to Duchenne muscular dystrophy are frequently associated with cognitive and behavioral deficits, suggesting a role for dystrophin in the nervous system. Despite significant progress over the past decade, many fundamental questions about the roles played by dystrophin and the other DGC proteins in the muscle and peripheral and central nervous systems remain to be answered. Mammalian models of DGC gene function are complicated by the existence of fully or partially redundant genes whose functions can mask effects of the inactivation of a given DGC gene. The genome of the fruitfly Drosophila melanogaster encodes a single ortholog of the majority of the mammalian DGC protein subclasses, thus potentially simplifying their functional analysis. We report here the embryonic mRNA expression patterns of the individual DGC orthologs. We find that they are predominantly expressed in the nervous system and in muscle. Dystrophin, dystrobrevin-like, dystroglycanlike, syntrophin-like 1, and all three sarcoglycan orthologs are found in the brain and the ventral nerve cord, while dystrophin, dystrobrevinlike, dystroglycan-like, syntrophin-like 2, sarcoglycan alpha and sarcoglycan delta are expressed in distinct and sometimes overlapping domains of mesoderm-derived tissues, i.e. muscles of the body wall and around the gut. Show less
