Catalytic properties, tissue and intracellular distribution of neurofibromin.
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.
Golubić
M
M
Department of Molecular Biology, Cleveland Clinic Foundation, Ohio 44195-5285.
Roudebush
M
M
Dobrowolski
S
S
Wolfman
A
A
Stacey
D W
DW
D000595:Amino Acid Sequence; D000818:Animals; D016718:Arachidonic Acid / Q000494:pharmacology; D001923:Brain Chemistry; D020558:GTP Phosphohydrolases / Q000032:analysis; D020690:GTPase-Activating Proteins; D007106:Immune Sera / Q000276:immunology; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D025542:Neurofibromin 1; D011506:Proteins / Q000032:analysis* / Q000276:immunology / Q000502:physiology; D011817:Rabbits; D020703:ras GTPase-Activating Proteins
D020690:GTPase-Activating Proteins; D007106:Immune Sera; D025542:Neurofibromin 1; D011506:Proteins; D020703:ras GTPase-Activating Proteins; D016718:Arachidonic Acid; D020558:GTP Phosphohydrolases