Pertussis toxin that encode Ptl proteins. Together, these proteins form the PT secretion complex. PT is released from "B. pertussis" in an inactive form. Following PT binding to a cell membrane receptor, it is taken up in an endosome, after which it undergoes retrograde transport to the trans-Golgi network and endoplasmic reticulum. At some point during this transport, the A subunit (or protomer) becomes activated, perhaps through the action of glutathione and ATP. PT catalyzes the ADP-ribosylation of the α subunits of the heterotrimeric G protein. This prevents the G proteins from interacting with G protein-coupled receptors on the cell membrane, thus
White line disease White line disease White line disease (also known as seedy toe) is a fungal infection of the horse's hoof. As the name suggests, it attacks the white line, which connects the sole to the hoof wall. It is sometimes mistaken for hoof wall separation disease, but is not to be confused because it is not genetic nor as severe. White line disease changes the typical light color of the white line to a black or dark gray color. It may also give off a foul odor. Lameness is often not present unless the disease is advanced. The disease may locate