A Schizophrenia-Linked KALRN Coding Variant Alters Neuron Morphology, Protein Function, and Transcript Stability
| Autor: | Peter Penzes, Katharine R. Smith, Katherine J. Kopeikina, Seok Kyu Kang, Theron A. Russell, Ruoqi Gao, Marc P. Forrest, Robert A. Sweet, Christine L. Remmers, Melanie J. Grubisha |
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| Rok vydání: | 2017 |
| Předmět: |
0301 basic medicine
Male Dendritic spine RHOA Protein Serine-Threonine Kinases Transfection Polymorphism Single Nucleotide 03 medical and health sciences 0302 clinical medicine Downregulation and upregulation Gene family Guanine Nucleotide Exchange Factors Humans RNA Messenger Gene Biological Psychiatry Genetics Neurons Messenger RNA biology HEK 293 cells Cell biology 030104 developmental biology HEK293 Cells biology.protein Schizophrenia Female Guanine nucleotide exchange factor 030217 neurology & neurosurgery |
| Zdroj: | Biological psychiatry. 83(6) |
| ISSN: | 1873-2402 |
| Popis: | Background Large-scale genetic studies have revealed that rare sequence variants, including single nucleotide variants (SNVs), in glutamatergic synaptic genes are enriched in schizophrenia patients. However, the majority are too rare to show any association with disease and have not been examined functionally. One such SNV, KALRN-P2255T, displays a penetrance that greatly exceeds that of previously identified schizophrenia-associated SNVs. Therefore, we sought to characterize its effects on the function of kalirin (Kal)-9, a dual Ras-related C3 botulinum toxin substrate 1 and Ras homologue gene family, member A (RhoA) guanine nucleotide exchange factor, upregulated in human schizophrenia brain tissue. Methods Kal9 was overexpressed in primary rat cortical neurons or human embryonic kidney 293 (HEK293) cells. The effects of the P2255T variant on dendritic branching, dendritic spine morphology, protein and messenger RNA stability, and catalytic activity were examined. Results Kal9-P2255T leads to diminished basal dendritic branching and dendritic spine size, compared with wild-type Kal9. The P2255T SNV directly affected Kal9 protein function, causing increased RhoA activation in HEK293 cells, but had no effect on Ras-related C3 botulinum toxin substrate 1 activation. Consistent with human postmortem findings, we found that Kal9-P2255T protein levels were higher than those of wild-type Kal9 in neurons. Increased messenger RNA stability was detected in HEK293 cells, indicating that this was the cause of the higher protein levels. When analyzed together, increased intrinsic RhoA guanine nucleotide exchange factor catalytic activity combined with increased messenger RNA expression led to net enhancement of RhoA activation, known to negatively impact neuronal morphology. Conclusions Taken together, our data reveal a novel mechanism for disease-associated SNVs and provide a platform for modeling morphological changes in mental disorders. |
| Databáze: | OpenAIRE |
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