TY - JOUR
T1 - Molecular and clinical analysis of RAF1 in Noonan syndrome and related disorders:Dephosphorylation of serine 259 as the essential mechanism for mutant activation
AU - Kobayashi, Tomoko
AU - Aoki, Yoko
AU - Niihori, Tetsuya
AU - Cavé, Hélène
AU - Verloes, Alain
AU - Okamoto, Nobuhiko
AU - Kawame, Hiroshi
AU - Fujiwara, Ikuma
AU - Takada, Fumio
AU - Ohata, Takako
AU - Sakazume, Satoru
AU - Ando, Tatsuya
AU - Nakagawa, Noriko
AU - Lapunzina, Pablo
AU - Meneses, Antonio G.
AU - Gillessen-Kaesbach, Gabriele
AU - Wieczorek, Dagmar
AU - Kurosawa, Kenji
AU - Mizuno, Seiji
AU - Ohashi, Hirofumi
AU - David, Albert
AU - Philip, Nicole
AU - Guliyeva, Afag
AU - Narumi, Yoko
AU - Kure, Shigeo
AU - Tsuchiya, Shigeru
AU - Matsubara, Yoichi
PY - 2010/3/1
Y1 - 2010/3/1
N2 - Noonan syndrome (NS) and related disorders are autosomal dominant disorders characterized by heart defects, facial dysmorphism, ectodermal abnormalities, and mental retardation. The dysregulation of the RAS/MAPK pathway appears to be a common molecular pathogenesis of these disorders: mutations in PTPN11, KRAS, and SOS1 have been identified in patients with NS, those in KRAS, BRAF, MAP2K1, and MAP2K2 in patients with CFC syndrome, and those in HRAS mutations in Costello syndrome patients. Recently, mutations in RAF1 have been also identified in patients with NS and two patients with LEOPARD (multiple lentigines, electrocardiographic conduction abnormalities, ocular hypertelorism, pulmonary stenosis, abnormal genitalia, retardation of growth, and sensorineural deafness) syndrome. In the current study, we identified eight RAF1 mutations in 18 of 119 patients with NS and related conditions without mutations in known genes. We summarized clinical manifestations in patients with RAF1 mutations as well as those in NS patients with PTPN11, SOS1, or KRAS mutations previously reported. Hypertrophic cardiomyopathy and short stature were found to be more frequently observed in patients with RAF1 mutations. Mutations in RAF1 were clustered in the conserved region 2 (CR2) domain, which carries an inhibitory phosphorylation site (serine at position 259; S259). Functional studies revealed that the RAF1 mutants located in the CR2 domain resulted in the decreased phosphorylation of S259, and that mutant RAF1 then dissociated from 14-3-3, leading to a partial ERK activation. Our results suggest that the dephosphorylation of S259 is the primary pathogenic mechanism in the activation of RAF1 mutants located in the CR2 domain as well as of downstream ERK.
AB - Noonan syndrome (NS) and related disorders are autosomal dominant disorders characterized by heart defects, facial dysmorphism, ectodermal abnormalities, and mental retardation. The dysregulation of the RAS/MAPK pathway appears to be a common molecular pathogenesis of these disorders: mutations in PTPN11, KRAS, and SOS1 have been identified in patients with NS, those in KRAS, BRAF, MAP2K1, and MAP2K2 in patients with CFC syndrome, and those in HRAS mutations in Costello syndrome patients. Recently, mutations in RAF1 have been also identified in patients with NS and two patients with LEOPARD (multiple lentigines, electrocardiographic conduction abnormalities, ocular hypertelorism, pulmonary stenosis, abnormal genitalia, retardation of growth, and sensorineural deafness) syndrome. In the current study, we identified eight RAF1 mutations in 18 of 119 patients with NS and related conditions without mutations in known genes. We summarized clinical manifestations in patients with RAF1 mutations as well as those in NS patients with PTPN11, SOS1, or KRAS mutations previously reported. Hypertrophic cardiomyopathy and short stature were found to be more frequently observed in patients with RAF1 mutations. Mutations in RAF1 were clustered in the conserved region 2 (CR2) domain, which carries an inhibitory phosphorylation site (serine at position 259; S259). Functional studies revealed that the RAF1 mutants located in the CR2 domain resulted in the decreased phosphorylation of S259, and that mutant RAF1 then dissociated from 14-3-3, leading to a partial ERK activation. Our results suggest that the dephosphorylation of S259 is the primary pathogenic mechanism in the activation of RAF1 mutants located in the CR2 domain as well as of downstream ERK.
UR - http://www.scopus.com/inward/record.url?scp=77149127346&partnerID=8YFLogxK
U2 - 10.1002/humu.21187
DO - 10.1002/humu.21187
M3 - Journal articles
C2 - 20052757
AN - SCOPUS:77149127346
SN - 1059-7794
VL - 31
SP - 284
EP - 294
JO - Human Mutation
JF - Human Mutation
IS - 3
ER -