TY - JOUR
T1 - A mutation in PAK3 with a dual molecular effect deregulates the RAS/MAPK pathway and drives an X-linked syndromic phenotype
AU - Magini, Pamela
AU - Pippucci, Tommaso
AU - Tsai, I. Chun
AU - Coppola, Simona
AU - Stellacci, Emilia
AU - Bartoletti-Stella, Anna
AU - Turchetti, Daniela
AU - Graziano, Claudio
AU - Cenacchi, Giovanna
AU - Neri, Iria
AU - Cordelli, Duccio Maria
AU - Marchiani, Valentina
AU - Bergamaschi, Rosalba
AU - Gasparre, Giuseppe
AU - Neri, Giovanni
AU - Mazzanti, Laura
AU - Patrizi, Annalisa
AU - Franzoni, Emilio
AU - Romeo, Giovanni
AU - Bordo, Domenico
AU - Tartaglia, Marco
AU - Katsanis, Nicholas
AU - Seri, Marco
PY - 2014
Y1 - 2014
N2 - Loss-of-function mutations in PAK3 contribute to non-syndromic X-linked intellectual disability (NS-XLID) by affecting dendritic spine density and morphology. Linkage analysis in a three-generation family with affected males showing ID, agenesis of corpus callosum, cerebellar hypoplasia, microcephaly and ichthyosis, revealed a candidate disease locus in Xq21.33q24 encompassing over 280 genes. Subsequent to sequencing all coding exons of the X chromosome, we identified a single novel variant within the linkage region, affecting a conserved codon of PAK3. Biochemical studies showed that, similar to previous NS-XLID-associated lesions, the predicted amino acid substitution (Lys389Asn) abolished the kinase activity of PAK3. In addition, the introduced residue conferred a dominant-negative function to the protein that drives the syndromic phenotype. Using a combination of in vitro and in vivo studies in zebrafish embryos,weshow that PAK3N389 escapes its physiologic degradation and is able to perturb MAPK signaling via an uncontrolled kinase-independent function, which in turn leads to alterations of cerebral and craniofacial structures in vivo. Our data expand the spectrum of phenotypes associated with PAK3 mutations, characterize a novel mechanism resulting in a dual molecular effect of the same mutation with a complex PAK3 functional deregulation and provide evidence for a direct functional impact of aberrant PAK3 function on MAPK signaling.
AB - Loss-of-function mutations in PAK3 contribute to non-syndromic X-linked intellectual disability (NS-XLID) by affecting dendritic spine density and morphology. Linkage analysis in a three-generation family with affected males showing ID, agenesis of corpus callosum, cerebellar hypoplasia, microcephaly and ichthyosis, revealed a candidate disease locus in Xq21.33q24 encompassing over 280 genes. Subsequent to sequencing all coding exons of the X chromosome, we identified a single novel variant within the linkage region, affecting a conserved codon of PAK3. Biochemical studies showed that, similar to previous NS-XLID-associated lesions, the predicted amino acid substitution (Lys389Asn) abolished the kinase activity of PAK3. In addition, the introduced residue conferred a dominant-negative function to the protein that drives the syndromic phenotype. Using a combination of in vitro and in vivo studies in zebrafish embryos,weshow that PAK3N389 escapes its physiologic degradation and is able to perturb MAPK signaling via an uncontrolled kinase-independent function, which in turn leads to alterations of cerebral and craniofacial structures in vivo. Our data expand the spectrum of phenotypes associated with PAK3 mutations, characterize a novel mechanism resulting in a dual molecular effect of the same mutation with a complex PAK3 functional deregulation and provide evidence for a direct functional impact of aberrant PAK3 function on MAPK signaling.
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U2 - 10.1093/hmg/ddu070
DO - 10.1093/hmg/ddu070
M3 - Article
C2 - 24556213
AN - SCOPUS:84902349968
VL - 23
SP - 3607
EP - 3617
JO - Human Molecular Genetics
JF - Human Molecular Genetics
SN - 0964-6906
IS - 13
M1 - ddu070
ER -