Review Question - QID 109682

A 38-year-old male is brought to the emergency department by ambulance after a motor vehicle collision. He is found to have a broken femur and multiple soft tissue injuries and is admitted to the hospital. During the hospital course, he is found to have lower extremity swelling, redness, and pain, so he is given an infusion of a medication. The intravenous medication is discontinued in favor of an oral medication in preparation for discharge; however, the patient leaves against medical advice prior to receiving the full set of instructions. The next day, the patient is found to have black lesions on his trunk and his leg. The protein involved in this patient's underlying abnormality most likely affects the function of which of the following factors?