Paxillin binds schwannomin and regulates its density-dependent localization and effect on cell morphology.
Neurofibromatosis type 2 is an autosomal dominant disorder characterized by tumors, predominantly schwannomas, in the nervous system. It is caused by mutations in the gene NF2, encoding the growth regulator schwannomin (also known as merlin). Mutations occur throughout the 17-exon gene, with most resulting in protein truncation and undetectable amounts of schwannomin protein. Pathogenic mutations that result in production of defective schwannomin include in-frame deletions of exon 2 and three independent missense mutations within this same exon. Mice with conditional deletion of exon 2 in Schwann cells develop schwannomas, which confirms the crucial nature of exon 2 for growth control. Here we report that the molecular adaptor paxillin binds directly to schwannomin at residues 50-70, which are encoded by exon 2. This interaction mediates the membrane localization of schwannomin to the plasma membrane, where it associates with beta 1 integrin and erbB2. It defines a pathogenic mechanism for the development of NF2 in humans with mutations in exon 2 of NF2.
Department of Molecular Biology and Microbiology, University of Central Florida, Orlando, Florida 32826, USA. cfernand@mail.ucf.edu
Cristina
C
Fernandez-Valle
Yong
Y
Tang
Jerome
J
Ricard
Alma
A
Rodenas-Ruano
Anna
A
Taylor
Elizabeth
E
Hackler
John
J
Biggerstaff
Jared
J
Iacovelli
D000818:Animals; D001665:Binding Sites; D002462:Cell Membrane / Q000378:metabolism*; D002478:Cells, Cultured; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D005091:Exons; D019012:Integrin beta1 / Q000378:metabolism; D051379:Mice; D009154:Mutation; D016518:Neurofibromatosis 2 / Q000235:genetics / Q000503:physiopathology; D025581:Neurofibromin 2 / Q000235:genetics* / Q000378:metabolism*; D051419:Paxillin; D010750:Phosphoproteins / Q000378:metabolism*; D020033:Protein Isoforms; D051381:Rats; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D012583:Schwann Cells / Q000166:cytology / Q000378:metabolism
D003598:Cytoskeletal Proteins; D019012:Integrin beta1; D025581:Neurofibromin 2; D051419:Paxillin; D010750:Phosphoproteins; D020033:Protein Isoforms; D018719:Erb-b2 Receptor Tyrosine Kinases; C496062:Pxn protein, mouse; C496063:Pxn protein, rat