Epidermal growth factor receptor
GTPase activating protein
NF-κB transcription factor
|D.||Ras protein p21|
Answer: B GTPase activating protein
Neurofibromatosis type 1 (NF1) is characterized by disfiguring neurofibromas, areas of dark pigmentation of the skin (café au lait spots), and pigmented lesions of the iris (Lisch nodules).
It is one of the more common autosomal dominant disorders. The NF1 gene has a high rate of mutation, and half of cases are sporadic rather than familial.
The protein product, termed neurofibromin, is expressed in many tissues and belongs to a family of GTPase-activating proteins (GAPs), which inactivate ras protein.
NF1 is a classic tumor suppressor gene. Loss of GAP activity (in cells acquiring a second hit mutation) permits uncontrolled ras p21 activation, an effect that predisposes to the formation of benign neurofibromas.