Catalytic properties, tissue and intracellular distribution of neurofibromin
Golubić, M.; Roudebush, M.; Dobrowolski, S.; Wolfman, A.; Stacey, D.W.
Oncogene 7(11): 2151-2159
1992
ISSN/ISBN: 0950-9232 PMID: 1437143 Document Number: 392507
The neurofibromatosis type 1 (NF1) gene encodes a protein, neurofibromin, that shows homology with members of the GTPase-activating protein (GAP) family. To study neurofibromin, rabbit polyclonal antisera were raised against two synthetic peptides. These antisera immunoprecipitated a specific protein of about 240 kDa in lysates of adult murine and rat tissues both in the soluble (S100) and to a lesser degree in the particulate (P100) fractions. The neurofibromin immunoprecipitated from the lysates of several murine organs stimulated the intrinsic GTPase activity of p21 c-Ha-ras protein. Based on immunoblotting, immunoprecipitation and GTPase assays, neurofibromin appears to be at least 10-fold more abundant in the brain than in the other murine organs. The GTPase-stimulatory activity of full-length neurofibromin, like the catalytic GAP-related domain, is inhibited by arachidonic acid and the detergent dodecyl maltoside, while phosphatidic acid, containing arachidonic and stearic acid, is non-inhibitory. Immunofluorescence analysis with anti-neurofibromin sera in NIH3T3 cells suggests that at least some of the cellular protein associates with cytoplasmic structures that are distinct from actin or tubulin filaments.