scholarly journals Protein expression of prenyltransferase subunits in postmortem schizophrenia dorsolateral prefrontal cortex

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Anita L. Pinner ◽  
Toni M. Mueller ◽  
Khaled Alganem ◽  
Robert McCullumsmith ◽  
James H. Meador-Woodruff
Keyword(s):  
Prefrontal Cortex ◽  
Protein Expression ◽  
Protein Interactions ◽  
Intracellular Signaling ◽  
Dorsolateral Prefrontal Cortex ◽  
Signaling Proteins ◽  
Protein Protein Interactions ◽  
Protein Prenylation ◽  
Lipid Modifications ◽  
Dorsolateral Prefrontal

AbstractThe pathophysiology of schizophrenia includes altered neurotransmission, dysregulated intracellular signaling pathway activity, and abnormal dendritic morphology that contribute to deficits of synaptic plasticity in the disorder. These processes all require dynamic protein–protein interactions at cell membranes. Lipid modifications target proteins to membranes by increasing substrate hydrophobicity by the addition of a fatty acid or isoprenyl moiety, and recent evidence suggests that dysregulated posttranslational lipid modifications may play a role in multiple neuropsychiatric disorders, including schizophrenia. Consistent with these emerging findings, we have recently reported decreased protein S-palmitoylation in schizophrenia. Protein prenylation is a lipid modification that occurs upstream of S-palmitoylation on many protein substrates, facilitating membrane localization and activity of key intracellular signaling proteins. Accordingly, we hypothesized that, in addition to palmitoylation, protein prenylation may be abnormal in schizophrenia. To test this, we assayed protein expression of the five prenyltransferase subunits (FNTA, FNTB, PGGT1B, RABGGTA, and RABGGTB) in postmortem dorsolateral prefrontal cortex from patients with schizophrenia and paired comparison subjects (n = 13 pairs). We found decreased levels of FNTA (14%), PGGT1B (13%), and RABGGTB (8%) in schizophrenia. To determine whether upstream or downstream factors may be driving these changes, we also assayed protein expression of the isoprenoid synthases FDPS and GGPS1 and prenylation-dependent processing enzymes RCE and ICMT. We found these upstream and downstream enzymes to have normal protein expression. To rule out effects from chronic antipsychotic treatment, we assayed FNTA, PGGT1B, and RABGGTB in the cortex from rats treated long-term with haloperidol decanoate and found no change in the expression of these proteins. Given the role prenylation plays in localization of key signaling proteins found at the synapse, these data offer a potential mechanism underlying abnormal protein–protein interactions and protein localization in schizophrenia.

scholarly journals Protein expression of prenyltransferase subunits in postmortem schizophrenia dorsolateral prefrontal cortex

2019 ◽  
Author(s):  
Anita L. Pinner ◽  
Toni M. Mueller ◽  
Khaled Alganem ◽  
Robert McCullumsmith ◽  
James H. Meador-Woodruff
Keyword(s):  
Prefrontal Cortex ◽  
Protein Expression ◽  
Protein Interactions ◽  
Intracellular Signaling ◽  
Dorsolateral Prefrontal Cortex ◽  
Signaling Proteins ◽  
Protein Protein Interactions ◽  
Protein Prenylation ◽  
Lipid Modifications ◽  
Dorsolateral Prefrontal

AbstractThe pathophysiology of schizophrenia includes altered neurotransmission, dysregulated intracellular signaling pathway activity, and abnormal dendritic morphology that contribute to deficits of synaptic plasticity in the disorder. These processes all require dynamic protein-protein interactions at cell membranes. Lipid modifications target proteins to membranes by increasing substrate hydrophobicity by the addition of a fatty acid or isoprenyl moiety, and recent evidence suggests that dysregulated post-translational lipid modifications may play a role in multiple neuropsychiatric disorders including schizophrenia. Consistent with these emerging findings, we have recently reported decreased protein S-palmitoylation in schizophrenia. Protein prenylation is a lipid modification that occurs upstream of S-palmitoylation on many protein substrates, facilitating membrane localization and activity of key intracellular signaling proteins. Accordingly, we hypothesized that in addition to palmitoylation, protein prenylation may be abnormal in schizophrenia. To test this, we assayed protein expression of the five prenyltransferase subunits (FNTA, FNTB, PGGT1B, RABGGTA, and RABGGTB) in postmortem dorsolateral prefrontal cortex from patients with schizophrenia and paired comparison subjects (N = 13 pairs). We found decreased levels of FNTA (14%), PGGT1B (13%), and RABGGTB (8%) in schizophrenia. To determine if upstream or downstream factors may be driving these changes, we also assayed protein expression of the isoprenoid synthases FDPS and GGPS1, and prenylation-dependent processing enzymes REC and ICMT. We found these upstream and downstream enzymes to have normal protein expression. To rule out effects from chronic antipsychotic treatment, we assayed FNTA, PGGT1B and RABGGTB in cortex from rats treated long-term with haloperidol decanoate, and found no change in the expression of these proteins. Given the role prenylation plays in localization of key signaling proteins found at the synapse, these data offer a potential mechanism underlying abnormal protein-protein interactions and protein localization in schizophrenia.

scholarly journals Mechanism of the G-protein mimetic nanobody binding to a muscarinic G-protein-coupled receptor

2018 ◽  
Vol 115 (12) ◽  
pp. 3036-3041 ◽  
Author(s):  
Yinglong Miao ◽  
J. Andrew McCammon
Keyword(s):  
Protein Binding ◽  
G Protein ◽  
Protein Interactions ◽  
Intracellular Signaling ◽  
Md Simulations ◽  
Binding Pocket ◽  
Signaling Proteins ◽  
Protein Protein Interactions ◽  
Intracellular Loops ◽  
G Protein Coupled

Protein–protein binding is key in cellular signaling processes. Molecular dynamics (MD) simulations of protein–protein binding, however, are challenging due to limited timescales. In particular, binding of the medically important G-protein-coupled receptors (GPCRs) with intracellular signaling proteins has not been simulated with MD to date. Here, we report a successful simulation of the binding of a G-protein mimetic nanobody to the M2 muscarinic GPCR using the robust Gaussian accelerated MD (GaMD) method. Through long-timescale GaMD simulations over 4,500 ns, the nanobody was observed to bind the receptor intracellular G-protein-coupling site, with a minimum rmsd of 2.48 Å in the nanobody core domain compared with the X-ray structure. Binding of the nanobody allosterically closed the orthosteric ligand-binding pocket, being consistent with the recent experimental finding. In the absence of nanobody binding, the receptor orthosteric pocket sampled open and fully open conformations. The GaMD simulations revealed two low-energy intermediate states during nanobody binding to the M2 receptor. The flexible receptor intracellular loops contribute remarkable electrostatic, polar, and hydrophobic residue interactions in recognition and binding of the nanobody. These simulations provided important insights into the mechanism of GPCR–nanobody binding and demonstrated the applicability of GaMD in modeling dynamic protein–protein interactions.

scholarly journals Classical complement cascade initiating C1q protein within neurons in the aged rhesus macaque dorsolateral prefrontal cortex

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Dibyadeep Datta ◽  
Shannon N. Leslie ◽  
Yury M. Morozov ◽  
Alvaro Duque ◽  
Pasko Rakic ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Rhesus Macaque ◽  
Protein Interactions ◽  
Dorsolateral Prefrontal Cortex ◽  
Rhesus Macaques ◽  
Inhibitory Synapses ◽  
Complement Cascade ◽  
Age Related ◽  
Dorsolateral Prefrontal ◽  
Age Related Changes

Abstract Background Cognitive impairment in schizophrenia, aging, and Alzheimer’s disease is associated with spine and synapse loss from the dorsolateral prefrontal cortex (dlPFC) layer III. Complement cascade signaling is critical in driving spine loss and disease pathogenesis. Complement signaling is initiated by C1q, which tags synapses for elimination. C1q is thought to be expressed predominately by microglia, but its expression in primate dlPFC has never been examined. The current study assayed C1q levels in aging primate dlPFC and rat medial PFC (mPFC) and used immunoelectron microscopy (immunoEM), immunoblotting, and co-immunoprecipitation (co-IP) to reveal the precise anatomical distribution and interactions of C1q. Methods Age-related changes in C1q levels in rhesus macaque dlPFC and rat mPFC were examined using immunoblotting. High-spatial resolution immunoEM was used to interrogate the subcellular localization of C1q in aged macaque layer III dlPFC and aged rat layer III mPFC. co-IP techniques quantified protein-protein interactions for C1q and proteins associated with excitatory and inhibitory synapses in macaque dlPFC. Results C1q levels were markedly increased in the aged macaque dlPFC. Ultrastructural localization found the expected C1q localization in glia, including those ensheathing synapses, but also revealed extensive localization within neurons. C1q was found near synapses, within terminals and in spines, but was also observed in dendrites, often near abnormal mitochondria. Similar analyses in aging rat mPFC corroborated the findings in rhesus macaques. C1q protein increasingly associated with PSD95 with age in macaque, consistent with its synaptic localization as evidenced by EM. Conclusions These findings reveal novel, intra-neuronal distribution patterns for C1q in the aging primate cortex, including evidence of C1q in dendrites. They suggest that age-related changes in the dlPFC may increase C1q expression and synaptic tagging for glial phagocytosis, a possible mechanism for age-related degeneration.

scholarly journals Alterations in Gene and Protein Expression of Cannabinoid CB2 and GPR55 Receptors in the Dorsolateral Prefrontal Cortex of Suicide Victims

2018 ◽  
Vol 15 (3) ◽  
pp. 796-806 ◽  
Author(s):  
María S. García-Gutiérrez ◽  
Francisco Navarrete ◽  
Gemma Navarro ◽  
Irene Reyes-Resina ◽  
Rafael Franco ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Protein Expression ◽  
Dorsolateral Prefrontal Cortex ◽  
Gene And Protein Expression ◽  
Dorsolateral Prefrontal

scholarly journals Differential sphingosine-1-phosphate receptor-1 (S1PR1) protein expressions in the dorsolateral prefrontal cortex between schizophrenia Type 1 and Type 2

2021 ◽  
Author(s):  
Ganesh B Chand ◽  
Hao Jiang ◽  
Matthew Brier ◽  
Farzaneh Rahmani ◽  
Tammie L. S. Benzinger ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Protein Expression ◽  
Dorsolateral Prefrontal Cortex ◽  
Clinical Test ◽  
Messenger Ribonucleic Acid ◽  
Dorsolateral Prefrontal ◽  
Sphingosine 1 Phosphate ◽  
Schizophrenic Patients

There is growing evidence that there are subtypes of schizophrenia (Bowen et al., 2019; Chand et al., 2020). Specifically, messenger ribonucleic acid (mRNA) gene expression findings on postmortem dorsolateral prefrontal cortex (DLPFC) suggest that schizophrenia patients can be divided into two groups, those with a relatively normal DLPFC transcriptome (Type 1) and those with hundreds of differentially expressed genes (Type 2). The clinical relevance of that finding is limited by the fact that autopsy tissue is required to distinguish Type 1 from Type 2 patients, however the PET target sphingosine-1-phosphate receptor-1 (S1PR1) is among the genes whose mRNA expression is upregulated in Type 2 compared to Type 1 patients (Bowen et al., 2019). As a preliminary study to validate this PET target, S1PR1 protein expression was assessed by receptor autoradiography and immunohistochemistry in the DLPFC from schizophrenic patients classified as Type 1 or Type 2 based on their DLPFC transcriptomes and from controls. S1PR1 protein expression is upregulated in Type 2 compared to Type 1 (p < 0.05) supporting the possibility that positron emission tomography (PET) can be used as a clinical test to distinguish these subgroups of schizophrenic patients during life.

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