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Hanes CM, Mah KM, Steffen DM, Marcucci CG, Fuller LC, Burgess RW, Garrett AM, Weiner JA. A C-terminal motif containing a PKC phosphorylation site regulates γ-Protocadherin-mediated dendrite arborization in the cerebral cortex in vivo. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.25.577214. [PMID: 38328061 PMCID: PMC10849722 DOI: 10.1101/2024.01.25.577214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
The Pcdhg gene cluster encodes 22 γ-Protocadherin (γ-Pcdh) cell adhesion molecules that critically regulate multiple aspects of neural development, including neuronal survival, dendritic and axonal arborization, and synapse formation and maturation. Each γ-Pcdh isoform has unique protein domains-a homophilically-interacting extracellular domain and a juxtamembrane cytoplasmic domain-as well as a C-terminal cytoplasmic domain shared by all isoforms. The extent to which isoform-specific vs. shared domains regulate distinct γ-Pcdh functions remains incompletely understood. Our previous in vitro studies identified PKC phosphorylation of a serine residue within a shared C-terminal motif as a mechanism through which γ-Pcdh promotion of dendrite arborization via MARCKS is abrogated. Here, we used CRISPR/Cas9 genome editing to generate two new mouse lines expressing only non-phosphorylatable γ-Pcdhs, due either to a serine-to-alanine mutation (PcdhgS/A) or to a 15-amino acid C-terminal deletion resulting from insertion of an early stop codon (PcdhgCTD). Both lines are viable and fertile, and the density and maturation of dendritic spines remains unchanged in both PcdhgS/A and PcdhgCTD cortex. Dendrite arborization of cortical pyramidal neurons, however, is significantly increased in both lines, as are levels of active MARCKS. Intriguingly, despite having significantly reduced levels of γ-Pcdh proteins, the PcdhgCTD mutation yields the strongest phenotype, with even heterozygous mutants exhibiting increased arborization. The present study confirms that phosphorylation of a shared C-terminal motif is a key γ-Pcdh negative regulation point, and contributes to a converging understanding of γ-Pcdh family function in which distinct roles are played by both individual isoforms and discrete protein domains.
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Affiliation(s)
- Camille M. Hanes
- Department of Biology, Iowa Neuroscience Institute, The University of Iowa, Iowa City, IA 52242
| | - Kar Men Mah
- Department of Biology, Iowa Neuroscience Institute, The University of Iowa, Iowa City, IA 52242
| | - David M. Steffen
- Department of Biology, Iowa Neuroscience Institute, The University of Iowa, Iowa City, IA 52242
| | - Charles G. Marcucci
- Department of Biology, Iowa Neuroscience Institute, The University of Iowa, Iowa City, IA 52242
| | - Leah C. Fuller
- Department of Biology, Iowa Neuroscience Institute, The University of Iowa, Iowa City, IA 52242
| | | | - Andrew M. Garrett
- Department of Pharmacology and Department of Ophthalmology, Visual, and Anatomical Sciences, Wayne State University, Detroit, MI 48202
| | - Joshua A. Weiner
- Department of Biology, Iowa Neuroscience Institute, The University of Iowa, Iowa City, IA 52242
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2
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Ptashnik A, LaMassa N, Mambetalieva A, Schnall E, Bucaro M, Phillips GR. Ubiquitination of the protocadherin-γA3 variable cytoplasmic domain modulates cell-cell interaction. Front Cell Dev Biol 2023; 11:1261048. [PMID: 37791076 PMCID: PMC10544333 DOI: 10.3389/fcell.2023.1261048] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 09/04/2023] [Indexed: 10/05/2023] Open
Abstract
The family of ∼60 clustered protocadherins (Pcdhs) are cell adhesion molecules encoded by a genomic locus that regulates expression of distinct combinations of isoforms in individual neurons resulting in what is thought to be a neural surface "barcode" which mediates same-cell interactions of dendrites, as well as interactions with other cells in the environment. Pcdh mediated same-cell dendrite interactions were shown to result in avoidance while interactions between different cells through Pcdhs, such as between neurons and astrocytes, appear to be stable. The cell biological mechanism of the consequences of Pcdh based adhesion is not well understood although various signaling pathways have been recently uncovered. A still unidentified cytoplasmic regulatory mechanism might contribute to a "switch" between avoidance and adhesion. We have proposed that endocytosis and intracellular trafficking could be part of such a switch. Here we use "stub" constructs consisting of the proximal cytoplasmic domain (lacking the constant carboxy-terminal domain spliced to all Pcdh-γs) of one Pcdh, Pcdh-γA3, to study trafficking. We found that the stub construct traffics primarily to Rab7 positive endosomes very similarly to the full length molecule and deletion of a substantial portion of the carboxy-terminus of the stub eliminates this trafficking. The intact stub was found to be ubiquitinated while the deletion was not and this ubiquitination was found to be at non-lysine sites. Further deletion mapping of the residues required for ubiquitination identified potential serine phosphorylation sites, conserved among Pcdh-γAs, that can reduce ubiquitination when pseudophosphorylated and increase surface expression. These results suggest Pcdh-γA ubiquitination can influence surface expression which may modulate adhesive activity during neural development.
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Affiliation(s)
- Albert Ptashnik
- Department of Biology, College of Staten Island, City University of New York, New York, NY, United States
- PhD Program in Biology, Subprogram in Neuroscience, CUNY Graduate Center, New York, NY, United States
| | - Nicole LaMassa
- Department of Biology, College of Staten Island, City University of New York, New York, NY, United States
- PhD Program in Biology, Subprogram in Neuroscience, CUNY Graduate Center, New York, NY, United States
| | - Aliya Mambetalieva
- Department of Biology, College of Staten Island, City University of New York, New York, NY, United States
| | - Emily Schnall
- Department of Biology, College of Staten Island, City University of New York, New York, NY, United States
| | - Mike Bucaro
- Department of Biology, College of Staten Island, City University of New York, New York, NY, United States
| | - Greg R. Phillips
- Department of Biology, College of Staten Island, City University of New York, New York, NY, United States
- PhD Program in Biology, Subprogram in Neuroscience, CUNY Graduate Center, New York, NY, United States
- Center for Developmental Neuroscience, College of Staten Island, City University of New York, New York, NY, United States
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3
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Steffen DM, Hanes CM, Mah KM, Valiño Ramos P, Bosch PJ, Hinz DC, Radley JJ, Burgess RW, Garrett AM, Weiner JA. A Unique Role for Protocadherin γC3 in Promoting Dendrite Arborization through an Axin1-Dependent Mechanism. J Neurosci 2023; 43:918-935. [PMID: 36604170 PMCID: PMC9908324 DOI: 10.1523/jneurosci.0729-22.2022] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 11/30/2022] [Accepted: 12/24/2022] [Indexed: 01/06/2023] Open
Abstract
The establishment of a functional cerebral cortex depends on the proper execution of multiple developmental steps, culminating in dendritic and axonal outgrowth and the formation and maturation of synaptic connections. Dysregulation of these processes can result in improper neuronal connectivity, including that associated with various neurodevelopmental disorders. The γ-Protocadherins (γ-Pcdhs), a family of 22 distinct cell adhesion molecules that share a C-terminal cytoplasmic domain, are involved in multiple aspects of neurodevelopment including neuronal survival, dendrite arborization, and synapse development. The extent to which individual γ-Pcdh family members play unique versus common roles remains unclear. We demonstrated previously that the γ-Pcdh-C3 isoform (γC3), via its unique "variable" cytoplasmic domain (VCD), interacts in cultured cells with Axin1, a Wnt-pathway scaffold protein that regulates the differentiation and morphology of neurons. Here, we confirm that γC3 and Axin1 interact in the cortex in vivo and show that both male and female mice specifically lacking γC3 exhibit disrupted Axin1 localization to synaptic fractions, without obvious changes in dendritic spine density or morphology. However, both male and female γC3 knock-out mice exhibit severely decreased dendritic complexity of cortical pyramidal neurons that is not observed in mouse lines lacking several other γ-Pcdh isoforms. Combining knock-out with rescue constructs in cultured cortical neurons pooled from both male and female mice, we show that γC3 promotes dendritic arborization through an Axin1-dependent mechanism mediated through its VCD. Together, these data identify a novel mechanism through which γC3 uniquely regulates the formation of cortical circuitry.SIGNIFICANCE STATEMENT The complexity of a neuron's dendritic arbor is critical for its function. We showed previously that the γ-Protocadherin (γ-Pcdh) family of 22 cell adhesion molecules promotes arborization during development; it remained unclear whether individual family members played unique roles. Here, we show that one γ-Pcdh isoform, γC3, interacts in the brain with Axin1, a scaffolding protein known to influence dendrite development. A CRISPR/Cas9-generated mutant mouse line lacking γC3 (but not lines lacking other γ-Pcdhs) exhibits severely reduced dendritic complexity of cerebral cortex neurons. Using cultured γC3 knock-out neurons and a variety of rescue constructs, we confirm that the γC3 cytoplasmic domain promotes arborization through an Axin1-dependent mechanism. Thus, γ-Pcdh isoforms are not interchangeable, but rather can play unique neurodevelopmental roles.
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Affiliation(s)
- David M Steffen
- Iowa Neuroscience Institute, The University of Iowa, Iowa City, Iowa 52242
- Department of Biology, The University of Iowa, Iowa City, Iowa 52242
| | - Camille M Hanes
- Iowa Neuroscience Institute, The University of Iowa, Iowa City, Iowa 52242
- Department of Biology, The University of Iowa, Iowa City, Iowa 52242
| | - Kar Men Mah
- Department of Biology, The University of Iowa, Iowa City, Iowa 52242
| | - Paula Valiño Ramos
- Iowa Neuroscience Institute, The University of Iowa, Iowa City, Iowa 52242
- Department of Biology, The University of Iowa, Iowa City, Iowa 52242
| | - Peter J Bosch
- Iowa Neuroscience Institute, The University of Iowa, Iowa City, Iowa 52242
- Department of Biology, The University of Iowa, Iowa City, Iowa 52242
| | - Dalton C Hinz
- Iowa Neuroscience Institute, The University of Iowa, Iowa City, Iowa 52242
- Department of Psychological and Brain Sciences, Program in Neuroscience, Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242
| | - Jason J Radley
- Iowa Neuroscience Institute, The University of Iowa, Iowa City, Iowa 52242
- Department of Psychological and Brain Sciences, Program in Neuroscience, Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242
| | | | - Andrew M Garrett
- Department of Pharmacology and Department of Ophthalmology, Visual, and Anatomical Sciences, Wayne State University, Detroit, Michigan 48202
| | - Joshua A Weiner
- Iowa Neuroscience Institute, The University of Iowa, Iowa City, Iowa 52242
- Department of Biology, The University of Iowa, Iowa City, Iowa 52242
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Hou S, Li G, Xu B, Dong H, Zhang S, Fu Y, Shi J, Li L, Fu J, Shi F, Meng Y, Jin Y. Trans-splicing facilitated by RNA pairing greatly expands sDscam isoform diversity but not homophilic binding specificity. SCIENCE ADVANCES 2022; 8:eabn9458. [PMID: 35857463 PMCID: PMC9258826 DOI: 10.1126/sciadv.abn9458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 05/21/2022] [Indexed: 06/15/2023]
Abstract
The Down syndrome cell adhesion molecule 1 (Dscam1) gene can generate tens of thousands of isoforms via alternative splicing, which is essential for nervous and immune functions. Chelicerates generate approximately 50 to 100 shortened Dscam (sDscam) isoforms by alternative promoters, similar to mammalian protocadherins. Here, we reveal that trans-splicing markedly increases the repository of sDscamβ isoforms in Tetranychus urticae. Unexpectedly, every variable exon cassette engages in trans-splicing with constant exons from another cluster. Moreover, we provide evidence that competing RNA pairing not only governs alternative cis-splicing but also facilitates trans-splicing. Trans-spliced sDscam isoforms mediate cell adhesion ability but exhibit the same homophilic binding specificity as their cis-spliced counterparts. Thus, we reveal a single sDscam locus that generates diverse adhesion molecules through cis- and trans-splicing coupled with alternative promoters. These findings expand understanding of the mechanism underlying molecular diversity and have implications for the molecular control of neuronal and/or immune specificity.
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Affiliation(s)
- Shouqing Hou
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, P. R. China
| | - Guo Li
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, P. R. China
| | - Bingbing Xu
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, P. R. China
| | - Haiyang Dong
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, P. R. China
| | - Shixin Zhang
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, P. R. China
| | - Ying Fu
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, P. R. China
| | - Jilong Shi
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, P. R. China
| | - Lei Li
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, P. R. China
| | - Jiayan Fu
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, P. R. China
| | - Feng Shi
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, P. R. China
| | - Yijun Meng
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, Zhejiang ZJ310018, P. R. China
| | - Yongfeng Jin
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, P. R. China
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5
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Xu Y, Zhang Y, Lopez IA, Hilbers J, Griswold AJ, Ishiyama A, Blanton S, Liu XZ, Lundberg YW. Identification of a genetic variant underlying familial cases of recurrent benign paroxysmal positional vertigo. PLoS One 2021; 16:e0251386. [PMID: 33956893 PMCID: PMC8101739 DOI: 10.1371/journal.pone.0251386] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 04/26/2021] [Indexed: 12/30/2022] Open
Abstract
Benign paroxysmal positional vertigo (BPPV) is the most common cause of vertigo in humans, yet the molecular etiology is currently unknown. Evidence suggests that genetic factors may play an important role in some cases of idiopathic BPPV, particularly in familial cases, but the responsible genetic variants have not been identified. In this study, we performed whole exome sequencing [including untranslated regions (UTRs)] of 12 families and Sanger sequencing of additional 30 families with recurrent BPPV in Caucasians from the United States (US) Midwest region, to identify the genetic variants responsible for heightened susceptibility to BPPV. Fifty non-BPPV families were included as controls. In silico and experimental analyses of candidate variants show that an insertion variant rs113784532 (frameshift causing truncation) in the neural cadherin gene PCDHGA10 (protocadherin-gamma A10) is an exceedingly strong candidate (p = 1.80x10-4 vs. sample controls; p = 5.85x10-19 vs. ExAC data; p = 4.9x10-3 vs. NHLBI exome data). The mutant protein forms large aggregates in BPPV samples even at young ages, and affected subjects carrying this variant have an earlier onset of the condition than those without [average 44.0±14.0 (n = 16) versus 54.4±16.1 (n = 36) years old, p = 0.054]. In both human and mouse inner ear tissues, PCDHGA10 is expressed in ganglia, hair cells and vestibular transitional epithelia. Fluorescent RNA in situ hybridization using mouse inner ear tissues shows that expression increases with age. In summary, our data show that a variant in the PCDHGA10 gene may be involved in causing or aggravating some familial cases of recurrent idiopathic BPPV.
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Affiliation(s)
- Yinfang Xu
- Vestibular Genetics Laboratory, Boys Town National Research Hospital, Omaha, Nebraska, United States of America
| | - Yan Zhang
- Vestibular Genetics Laboratory, Boys Town National Research Hospital, Omaha, Nebraska, United States of America
| | - Ivan A. Lopez
- Department of Head and Neck Surgery, “David Geffen” School of Medicine at The University of California at Los Angeles, Los Angeles, California, United States of America
| | - Jacey Hilbers
- Vestibular Genetics Laboratory, Boys Town National Research Hospital, Omaha, Nebraska, United States of America
| | - Anthony J. Griswold
- Department of Human Genetics and John P. Hussman Institute for Human Genomics, Dr. John T. Macdonald Foundation, University of Miami Miller School of Medicine, Miami, Florida, United States of America
| | - Akira Ishiyama
- Department of Head and Neck Surgery, “David Geffen” School of Medicine at The University of California at Los Angeles, Los Angeles, California, United States of America
| | - Susan Blanton
- Department of Human Genetics and John P. Hussman Institute for Human Genomics, Dr. John T. Macdonald Foundation, University of Miami Miller School of Medicine, Miami, Florida, United States of America
- Department of Otolaryngology, The University of Miami Miller School of Medicine, Miami, Florida, United States of America
| | - Xue Zhong Liu
- Department of Human Genetics and John P. Hussman Institute for Human Genomics, Dr. John T. Macdonald Foundation, University of Miami Miller School of Medicine, Miami, Florida, United States of America
- Department of Otolaryngology, The University of Miami Miller School of Medicine, Miami, Florida, United States of America
| | - Yunxia Wang Lundberg
- Vestibular Genetics Laboratory, Boys Town National Research Hospital, Omaha, Nebraska, United States of America
- * E-mail:
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6
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Jia Z, Wu Q. Clustered Protocadherins Emerge as Novel Susceptibility Loci for Mental Disorders. Front Neurosci 2020; 14:587819. [PMID: 33262685 PMCID: PMC7688460 DOI: 10.3389/fnins.2020.587819] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 10/26/2020] [Indexed: 12/24/2022] Open
Abstract
The clustered protocadherins (cPcdhs) are a subfamily of type I single-pass transmembrane cell adhesion molecules predominantly expressed in the brain. Their stochastic and combinatorial expression patterns encode highly diverse neural identity codes which are central for neuronal self-avoidance and non-self discrimination in brain circuit formation. In this review, we first briefly outline mechanisms for generating a tremendous diversity of cPcdh cell-surface assemblies. We then summarize the biological functions of cPcdhs in a wide variety of neurodevelopmental processes, such as neuronal migration and survival, dendritic arborization and self-avoidance, axonal tiling and even spacing, and synaptogenesis. We focus on genetic, epigenetic, and 3D genomic dysregulations of cPcdhs that are associated with various neuropsychiatric and neurodevelopmental diseases. A deeper understanding of regulatory mechanisms and physiological functions of cPcdhs should provide significant insights into the pathogenesis of mental disorders and facilitate development of novel diagnostic and therapeutic strategies.
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Affiliation(s)
| | - Qiang Wu
- Center for Comparative Biomedicine, MOE Key Laboratory of Systems Biomedicine, State Key Laboratory of Oncogenes and Related Genes, School of Life Sciences and Biotechnology, Institute of Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, China
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7
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The γ-Protocadherins Regulate the Survival of GABAergic Interneurons during Developmental Cell Death. J Neurosci 2020; 40:8652-8668. [PMID: 33060174 DOI: 10.1523/jneurosci.1636-20.2020] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 09/23/2020] [Accepted: 09/29/2020] [Indexed: 12/15/2022] Open
Abstract
Inhibitory interneurons integrate into developing circuits in specific ratios and distributions. In the neocortex, inhibitory network formation occurs concurrently with the apoptotic elimination of a third of GABAergic interneurons. The cell surface molecules that select interneurons to survive or die are unknown. Here, we report that members of the clustered Protocadherins (cPCDHs) control GABAergic interneuron survival during developmentally-regulated cell death. Conditional deletion of the gene cluster encoding the γ-Protocadherins (Pcdhgs) from developing GABAergic neurons in mice of either sex causes a severe loss of inhibitory populations in multiple brain regions and results in neurologic deficits such as seizures. By focusing on the neocortex and the cerebellar cortex, we demonstrate that reductions of inhibitory interneurons result from elevated apoptosis during the critical postnatal period of programmed cell death (PCD). By contrast, cortical interneuron (cIN) populations are not affected by removal of Pcdhgs from pyramidal neurons or glial cells. Interneuron loss correlates with reduced AKT signaling in Pcdhg mutant interneurons, and is rescued by genetic blockade of the pro-apoptotic factor BAX. Together, these findings identify the PCDHGs as pro-survival transmembrane proteins that select inhibitory interneurons for survival and modulate the extent of PCD. We propose that the PCDHGs contribute to the formation of balanced inhibitory networks by controlling the size of GABAergic interneuron populations in the developing brain.SIGNIFICANCE STATEMENT A pivotal step for establishing appropriate excitatory-inhibitory ratios is adjustment of neuronal populations by cell death. In the mouse neocortex, a third of GABAergic interneurons are eliminated by BAX-dependent apoptosis during the first postnatal week. Interneuron cell death is modulated by neural activity and pro-survival pathways but the cell-surface molecules that select interneurons for survival or death are unknown. We demonstrate that members of the cadherin superfamily, the clustered γ-Protocadherins (PCDHGs), regulate the survival of inhibitory interneurons and the balance of cell death. Deletion of the Pcdhgs in mice causes inhibitory interneuron loss in the cortex and cerebellum, and leads to motor deficits and seizures. Our findings provide a molecular basis for controlling inhibitory interneuron population size during circuit formation.
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8
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Pancho A, Aerts T, Mitsogiannis MD, Seuntjens E. Protocadherins at the Crossroad of Signaling Pathways. Front Mol Neurosci 2020; 13:117. [PMID: 32694982 PMCID: PMC7339444 DOI: 10.3389/fnmol.2020.00117] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 06/08/2020] [Indexed: 12/25/2022] Open
Abstract
Protocadherins (Pcdhs) are cell adhesion molecules that belong to the cadherin superfamily, and are subdivided into clustered (cPcdhs) and non-clustered Pcdhs (ncPcdhs) in vertebrates. In this review, we summarize their discovery, expression mechanisms, and roles in neuronal development and cancer, thereby highlighting the context-dependent nature of their actions. We furthermore provide an extensive overview of current structural knowledge, and its implications concerning extracellular interactions between cPcdhs, ncPcdhs, and classical cadherins. Next, we survey the known molecular action mechanisms of Pcdhs, emphasizing the regulatory functions of proteolytic processing and domain shedding. In addition, we outline the importance of Pcdh intracellular domains in the regulation of downstream signaling cascades, and we describe putative Pcdh interactions with intracellular molecules including components of the WAVE complex, the Wnt pathway, and apoptotic cascades. Our overview combines molecular interaction data from different contexts, such as neural development and cancer. This comprehensive approach reveals potential common Pcdh signaling hubs, and points out future directions for research. Functional studies of such key factors within the context of neural development might yield innovative insights into the molecular etiology of Pcdh-related neurodevelopmental disorders.
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Affiliation(s)
- Anna Pancho
- Laboratory of Developmental Neurobiology, Department of Biology, KU Leuven, Leuven, Belgium
| | - Tania Aerts
- Laboratory of Developmental Neurobiology, Department of Biology, KU Leuven, Leuven, Belgium
| | - Manuela D Mitsogiannis
- Laboratory of Developmental Neurobiology, Department of Biology, KU Leuven, Leuven, Belgium
| | - Eve Seuntjens
- Laboratory of Developmental Neurobiology, Department of Biology, KU Leuven, Leuven, Belgium
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9
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Miralles CP, Taylor MJ, Bear J, Fekete CD, George S, Li Y, Bonhomme B, Chiou TT, De Blas AL. Expression of protocadherin-γC4 protein in the rat brain. J Comp Neurol 2019; 528:840-864. [PMID: 31609469 DOI: 10.1002/cne.24783] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 09/24/2019] [Accepted: 09/30/2019] [Indexed: 12/26/2022]
Abstract
It has been proposed that the combinatorial expression of γ-protocadherins (Pcdh-γs) and other clustered protocadherins (Pcdhs) provides a code of molecular identity and individuality to neurons, which plays a major role in the establishment of specific synaptic connectivity and formation of neuronal circuits. Particular attention has been directed to the Pcdh-γ family, for which experimental evidence derived from Pcdh-γ-deficient mice shows that they are involved in dendrite self-avoidance, synapse development, dendritic arborization, spine maturation, and prevention of apoptosis of some neurons. Moreover, a triple-mutant mouse deficient in the three C-type members of the Pcdh-γ family (Pcdh-γC3, Pcdh-γC4, and Pcdh-γC5) shows a phenotype similar to the mouse deficient in whole Pcdh-γ family, indicating that the latter is largely due to the absence of C-type Pcdh-γs. The role of each individual C-type Pcdh-γ is not known. We have developed a specific antibody to Pcdh-γC4 to reveal the expression of this protein in the rat brain. The results show that although Pcdh-γC4 is expressed at higher levels in the embryo and earlier postnatal weeks, it is also expressed in the adult rat brain. Pcdh-γC4 is expressed in both neurons and astrocytes. In the adult brain, the regional distribution of Pcdh-γC4 immunoreactivity is similar to that of Pcdh-γC4 mRNA, being highest in the olfactory bulb, dentate gyrus, and cerebellum. Pcdh-γC4 forms puncta that are frequently apposed to glutamatergic and GABAergic synapses. They are also frequently associated with neuron-astrocyte contacts. The results provide new insights into the cell recognition function of Pcdh-γC4 in neurons and astrocytes.
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Affiliation(s)
- Celia P Miralles
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Michael J Taylor
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - John Bear
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Christopher D Fekete
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Shanu George
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Yanfang Li
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Bevan Bonhomme
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Tzu-Ting Chiou
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Angel L De Blas
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
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10
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Fan L, Lu Y, Shen X, Shao H, Suo L, Wu Q. Alpha protocadherins and Pyk2 kinase regulate cortical neuron migration and cytoskeletal dynamics via Rac1 GTPase and WAVE complex in mice. eLife 2018; 7:e35242. [PMID: 29911975 PMCID: PMC6047886 DOI: 10.7554/elife.35242] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 06/11/2018] [Indexed: 02/06/2023] Open
Abstract
Diverse clustered protocadherins are thought to function in neurite morphogenesis and neuronal connectivity in the brain. Here, we report that the protocadherin alpha (Pcdha) gene cluster regulates neuronal migration during cortical development and cytoskeletal dynamics in primary cortical culture through the WAVE (Wiskott-Aldrich syndrome family verprolin homologous protein, also known as Wasf) complex. In addition, overexpression of proline-rich tyrosine kinase 2 (Pyk2, also known as Ptk2b, Cakβ, Raftk, Fak2, and Cadtk), a non-receptor cell-adhesion kinase and scaffold protein downstream of Pcdhα, impairs cortical neuron migration via inactivation of the small GTPase Rac1. Thus, we define a molecular Pcdhα/WAVE/Pyk2/Rac1 axis from protocadherin cell-surface receptors to actin cytoskeletal dynamics in cortical neuron migration and dendrite morphogenesis in mouse brain.
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Affiliation(s)
- Li Fan
- Key Laboratory of Systems Biomedicine (Ministry of Education), Center for Comparative Biomedicine, Institute of Systems Biomedicine, Shanghai Center for Systems BiomedicineShanghai Jiao Tong UniversityShanghaiChina
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer InstituteRenji Hospital affiliated to Shanghai Jiao Tong University Medical SchoolShanghaiChina
- School of Life Sciences and BiotechnologyShanghai Jiao Tong UniversityShanghaiChina
| | - Yichao Lu
- Key Laboratory of Systems Biomedicine (Ministry of Education), Center for Comparative Biomedicine, Institute of Systems Biomedicine, Shanghai Center for Systems BiomedicineShanghai Jiao Tong UniversityShanghaiChina
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer InstituteRenji Hospital affiliated to Shanghai Jiao Tong University Medical SchoolShanghaiChina
- School of Life Sciences and BiotechnologyShanghai Jiao Tong UniversityShanghaiChina
| | - Xiulian Shen
- Key Laboratory of Systems Biomedicine (Ministry of Education), Center for Comparative Biomedicine, Institute of Systems Biomedicine, Shanghai Center for Systems BiomedicineShanghai Jiao Tong UniversityShanghaiChina
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer InstituteRenji Hospital affiliated to Shanghai Jiao Tong University Medical SchoolShanghaiChina
- School of Life Sciences and BiotechnologyShanghai Jiao Tong UniversityShanghaiChina
| | - Hong Shao
- Key Laboratory of Systems Biomedicine (Ministry of Education), Center for Comparative Biomedicine, Institute of Systems Biomedicine, Shanghai Center for Systems BiomedicineShanghai Jiao Tong UniversityShanghaiChina
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer InstituteRenji Hospital affiliated to Shanghai Jiao Tong University Medical SchoolShanghaiChina
- School of Life Sciences and BiotechnologyShanghai Jiao Tong UniversityShanghaiChina
| | - Lun Suo
- Key Laboratory of Systems Biomedicine (Ministry of Education), Center for Comparative Biomedicine, Institute of Systems Biomedicine, Shanghai Center for Systems BiomedicineShanghai Jiao Tong UniversityShanghaiChina
- Department of Assisted ReproductionShanghai Jiao Tong University Medical SchoolShanghaiChina
| | - Qiang Wu
- Key Laboratory of Systems Biomedicine (Ministry of Education), Center for Comparative Biomedicine, Institute of Systems Biomedicine, Shanghai Center for Systems BiomedicineShanghai Jiao Tong UniversityShanghaiChina
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer InstituteRenji Hospital affiliated to Shanghai Jiao Tong University Medical SchoolShanghaiChina
- School of Life Sciences and BiotechnologyShanghai Jiao Tong UniversityShanghaiChina
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Phillips GR, LaMassa N, Nie YM. Clustered protocadherin trafficking. Semin Cell Dev Biol 2017; 69:131-139. [PMID: 28478299 DOI: 10.1016/j.semcdb.2017.05.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 04/26/2017] [Accepted: 05/03/2017] [Indexed: 12/20/2022]
Abstract
The cluster of almost 60 protocadherin genes, divided into the α, β and γ subgroups, is a hallmark of vertebrate nervous system evolution. These clustered protocadherins (Pcdhs) are of interest for several reasons, one being the arrangement of the genes, which allows epigenetic regulation at the cluster and single-cell identity. Another reason is the still ambiguous effect of Pcdhs on cell-cell interaction. Unlike the case for classical cadherins, which typically mediate strong cell adhesion and formation of adherens junctions, it has been challenging to ascertain exactly how Pcdhs affect interacting cells. In some instances, Pcdhs appear to promote the association of membranes, while in other cases the Pcdhs are anti-adhesive and cause avoidance of interacting membranes. It is clear that Pcdh extracellular domains bind homophillically in an antiparallel conformation, typical of adhesive interactions. How can molecules that would seemingly bind cells together be able to promote the avoidance of membranes? It is possible that Pcdh trafficking will eventually provide insights into the role of these molecules at the cell surface. We have found that endogenous and expressed Pcdhs are generally less efficient at targeting to cell junctions and synapses than are classical cadherins. Instead, Pcdhs are prominently sequestered in the endolysosome system or other intracellular compartments. What role this trafficking plays in the unique mode of cell-cell interaction is a current topic of investigation. It is tempting to speculate that modulation of endocytosis and endolysosomal trafficking may be a part of the mechanism by which Pcdhs convert from adhesive to avoidance molecules.
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Affiliation(s)
- Greg R Phillips
- Department of Biology, Center for Developmental Neuroscience, College of Staten Island, City University of New York, United States; Program in Neuroscience, The Graduate Center, City University of New York, United States.
| | - Nicole LaMassa
- Department of Biology, Center for Developmental Neuroscience, College of Staten Island, City University of New York, United States
| | - Yan Mei Nie
- Department of Biology, Center for Developmental Neuroscience, College of Staten Island, City University of New York, United States
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