TY - JOUR
T1 - Functional evaluation of autism-associated mutations in NHE9
AU - Kondapalli, Kalyan C.
AU - Hack, Anniesha
AU - Schushan, Maya
AU - Landau, Meytal
AU - Ben-Tal, Nir
AU - Rao, Rajini
PY - 2013
Y1 - 2013
N2 - NHE9 (SLC9A9) is an endosomal cation/proton antiporter with orthologues in yeast and bacteria. Rare, missense substitutions in NHE9 are genetically linked with autism but have not been functionally evaluated. Here we use evolutionary conservation analysis to build a model structure of NHE9 based on the crystal structure of bacterial NhaA and use it to screen autism-associated variants in the human population first by phenotype complementation in yeast, followed by functional analysis in primary cortical astrocytes from mouse. NHE9-GFP localizes to recycling endosomes, where it significantly alkalinizes luminal pH, elevates uptake of transferrin and the neurotransmitter glutamate, and stabilizes surface expression of transferrin receptor and GLAST transporter. In contrast, autism-associated variants L236S, S438P and V176I lack function in astrocytes. Thus, we establish a neurobiological cell model of a candidate gene in autism. Loss-of-function mutations in NHE9 may contribute to autistic phenotype by modulating synaptic membrane protein expression and neurotransmitter clearance.
AB - NHE9 (SLC9A9) is an endosomal cation/proton antiporter with orthologues in yeast and bacteria. Rare, missense substitutions in NHE9 are genetically linked with autism but have not been functionally evaluated. Here we use evolutionary conservation analysis to build a model structure of NHE9 based on the crystal structure of bacterial NhaA and use it to screen autism-associated variants in the human population first by phenotype complementation in yeast, followed by functional analysis in primary cortical astrocytes from mouse. NHE9-GFP localizes to recycling endosomes, where it significantly alkalinizes luminal pH, elevates uptake of transferrin and the neurotransmitter glutamate, and stabilizes surface expression of transferrin receptor and GLAST transporter. In contrast, autism-associated variants L236S, S438P and V176I lack function in astrocytes. Thus, we establish a neurobiological cell model of a candidate gene in autism. Loss-of-function mutations in NHE9 may contribute to autistic phenotype by modulating synaptic membrane protein expression and neurotransmitter clearance.
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U2 - 10.1038/ncomms3510
DO - 10.1038/ncomms3510
M3 - Article
C2 - 24065030
AN - SCOPUS:84885145782
VL - 4
JO - Nature Communications
JF - Nature Communications
SN - 2041-1723
M1 - 2510
ER -