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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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Hoshino N, Kanadome T, Takasugi T, Itoh M, Kaneko R, Inoue YU, Inoue T, Hirabayashi T, Watanabe M, Matsuda T, Nagai T, Tarusawa E, Yagi T. Visualization of trans homophilic interaction of clustered protocadherin in neurons. Proc Natl Acad Sci U S A 2023; 120:e2301003120. [PMID: 37695902 PMCID: PMC10515168 DOI: 10.1073/pnas.2301003120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 07/20/2023] [Indexed: 09/13/2023] Open
Abstract
Clustered protocadherin (Pcdh) functions as a cell recognition molecule through the homophilic interaction in the central nervous system. However, its interactions have not yet been visualized in neurons. We previously reported PcdhγB2-Förster resonance energy transfer (FRET) probes to be applicable only to cell lines. Herein, we designed γB2-FRET probes by fusing FRET donor and acceptor fluorescent proteins to a single γB2 molecule and succeeded in visualizing γB2 homophilic interaction in cultured hippocampal neurons. The γB2-FRET probe localized in the soma and neurites, and FRET signals, which were observed at contact sites between neurites, eliminated by ethylene glycol tetraacetic acid (EGTA) addition. Live imaging revealed that the FRET-negative γB2 signals rapidly moved along neurites and soma, whereas the FRET-positive signals remained in place. We observed that the γB2 proteins at synapses rarely interact homophilically. The γB2-FRET probe might allow us to elucidate the function of the homophilic interaction and the cell recognition mechanism.
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Affiliation(s)
- Natsumi Hoshino
- KOKORO-Biology Group, Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka565-0871, Japan
| | - Takashi Kanadome
- Department of Biomolecular Science and Engineering, SANKEN, Osaka University, Ibaraki, Osaka567-0047, Japan
- Japan Science and Technology Agency, Precursory Research for Embryonic Science and Technology, Kawaguchi, Saitama332-0012, Japan
| | - Tomomi Takasugi
- KOKORO-Biology Group, Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka565-0871, Japan
| | - Mizuho Itoh
- KOKORO-Biology Group, Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka565-0871, Japan
| | - Ryosuke Kaneko
- KOKORO-Biology Group, Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka565-0871, Japan
| | - Yukiko U. Inoue
- Department of Biochemistry and Cellular Biology, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo187-8501, Japan
| | - Takayoshi Inoue
- Department of Biochemistry and Cellular Biology, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo187-8501, Japan
| | - Takahiro Hirabayashi
- KOKORO-Biology Group, Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka565-0871, Japan
- Clinical Medicine Research Laboratory, Shonan University of Medical Sciences, Yokohama244-0806, Japan
| | - Masahiko Watanabe
- Department of Anatomy, Faculty of Medicine, Hokkaido University, Sapporo, Hokkaido060-8638, Japan
| | - Tomoki Matsuda
- Department of Biomolecular Science and Engineering, SANKEN, Osaka University, Ibaraki, Osaka567-0047, Japan
| | - Takeharu Nagai
- Department of Biomolecular Science and Engineering, SANKEN, Osaka University, Ibaraki, Osaka567-0047, Japan
| | - Etsuko Tarusawa
- KOKORO-Biology Group, Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka565-0871, Japan
| | - Takeshi Yagi
- KOKORO-Biology Group, Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka565-0871, Japan
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3
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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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4
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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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5
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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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6
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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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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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8
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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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9
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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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10
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Epigenetic dysregulation of protocadherins in human disease. Semin Cell Dev Biol 2017; 69:172-182. [PMID: 28694114 DOI: 10.1016/j.semcdb.2017.07.007] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 07/03/2017] [Accepted: 07/06/2017] [Indexed: 12/12/2022]
Abstract
Protocadherins (Pcdhs) are a group of cell-cell adhesion molecules that are highly expressed in the nervous system and have a major function in dendrite development and neural circuit formation. However, the role protocadherins play in human health and disease remains unclear. Several recent studies have associated epigenetic dysregulation of protocadherins with possible implications for disease pathogenesis. In this review, we briefly recap the various epigenetic mechanisms regulating protocadherin genes, particularly the clustered Pcdhs. We further outline research describing altered epigenetic regulation of protocadherins in neurological and psychiatric disorders, as well as in cancer and during aging. We additionally present preliminary data on DNA methylation dynamics of clustered protocadherins during fetal brain development, as well as the epigenetic differences distinguishing adult neuronal and glial cells. A deeper understanding of the role of protocadherins in disease is crucial for designing novel diagnostic tools and therapies targeting brain disorders.
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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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Shonubi A, Roman C, Phillips GR. The clustered protocadherin endolysosomal trafficking motif mediates cytoplasmic association. BMC Cell Biol 2015; 16:28. [PMID: 26608278 PMCID: PMC4660814 DOI: 10.1186/s12860-015-0074-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2015] [Accepted: 11/12/2015] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Clustered protocadherins (Pcdhs) are a large family of neural cadherin-like proteins encoded by individual exons located within three gene clusters. Each exon codes an extracellular, transmembrane, and proximal cytoplasmic domain. These "variable" regions may be spliced to a constant cytoplasmic moiety encoded at the end of a cluster. Pcdh extracellular domains mediate homophilic cell-cell binding but their cytoplasmic domains cause intracellular retention and may negatively regulate Pcdh cell-cell binding. Pcdhs can be found at the cell surface in neurons and other cells but are also, unlike classical cadherins, prominently trafficked to the endolysosome system. It was previously found that a segment within the variable portion of the Pcdh-γA3 cytoplasmic domain (VCD) was shown to be necessary for endolysosomal trafficking. RESULTS Here it is shown that this same VCD segment can mediate cytoplasmic association among Pcdhs from the different clusters. Internal deletions within this VCD region (termed here the VCD motif) that disrupt the association altered trafficking of Pcdh-γA3 in the endolysosomal system while deletions outside VCD motif did not affect trafficking. CONCLUSIONS The results show that Pcdhs associate cytoplasmically via a motif within the VCD and that this is critical for Pcdh trafficking. Given that truncation at the VCD motif alters endolysosomal trafficking of Pcdhs, the VCD interaction described here may provide new insights into the dynamic nature of Pcdh mediated cell-cell interactions.
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Affiliation(s)
- Adam Shonubi
- Department of Biology, College of Staten Island, City University of New York, 2800 Victory Blvd, Staten Island, NY, 10314, USA.
| | - Chantelle Roman
- Department of Biology, College of Staten Island, City University of New York, 2800 Victory Blvd, Staten Island, NY, 10314, USA.
| | - Greg R Phillips
- Department of Biology, College of Staten Island, City University of New York, 2800 Victory Blvd, Staten Island, NY, 10314, USA. .,Center for Developmental Neuroscience, College of Staten Island, City University of New York, 2800 Victory Blvd, Staten Island, NY, 10314, USA. .,CUNY Graduate Center, College of Staten Island, City University of New York, 2800 Victory Blvd, Staten Island, NY, 10314, USA.
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Keeler AB, Schreiner D, Weiner JA. Protein Kinase C Phosphorylation of a γ-Protocadherin C-terminal Lipid Binding Domain Regulates Focal Adhesion Kinase Inhibition and Dendrite Arborization. J Biol Chem 2015; 290:20674-20686. [PMID: 26139604 DOI: 10.1074/jbc.m115.642306] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Indexed: 11/06/2022] Open
Abstract
The γ-protocadherins (γ-Pcdhs) are a family of 22 adhesion molecules with multiple critical developmental functions, including the proper formation of dendritic arbors by forebrain neurons. The γ-Pcdhs bind to and inhibit focal adhesion kinase (FAK) via a constant C-terminal cytoplasmic domain shared by all 22 proteins. In cortical neurons lacking the γ-Pcdhs, aberrantly high activity of FAK and of PKC disrupts dendrite arborization. Little is known, however, about how γ-Pcdh function is regulated by other factors. Here we show that PKC phosphorylates a serine residue situated within a phospholipid binding motif at the shared γ-Pcdh C terminus. Western blots using a novel phospho-specific antibody against this site suggest that a portion of γ-Pcdh proteins is phosphorylated in the cortex in vivo. We find that PKC phosphorylation disrupts both phospholipid binding and the γ-Pcdh inhibition of (but not binding to) FAK. Introduction of a non-phosphorylatable (S922A) γ-Pcdh construct into wild-type cortical neurons significantly increases dendrite arborization. This same S922A construct can also rescue dendrite arborization defects in γ-Pcdh null neurons cell autonomously. Consistent with these data, introduction of a phosphomimetic (S/D) γ-Pcdh construct or treatment with a PKC activator reduces dendrite arborization in wild-type cortical neurons. Together, these data identify a novel mechanism through which γ-Pcdh control of a signaling pathway important for dendrite arborization is regulated.
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Affiliation(s)
- Austin B Keeler
- Department of Biology, The University of Iowa, Iowa City, Iowa 52242; Neuroscience Graduate Program, The University of Iowa, Iowa City, Iowa 52242
| | - Dietmar Schreiner
- Department of Biology, The University of Iowa, Iowa City, Iowa 52242
| | - Joshua A Weiner
- Department of Biology, The University of Iowa, Iowa City, Iowa 52242; Neuroscience Graduate Program, The University of Iowa, Iowa City, Iowa 52242.
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Friedman LG, Benson DL, Huntley GW. Cadherin-based transsynaptic networks in establishing and modifying neural connectivity. Curr Top Dev Biol 2015; 112:415-65. [PMID: 25733148 DOI: 10.1016/bs.ctdb.2014.11.025] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
It is tacitly understood that cell adhesion molecules (CAMs) are critically important for the development of cells, circuits, and synapses in the brain. What is less clear is what CAMs continue to contribute to brain structure and function after the early period of development. Here, we focus on the cadherin family of CAMs to first briefly recap their multidimensional roles in neural development and then to highlight emerging data showing that with maturity, cadherins become largely dispensible for maintaining neuronal and synaptic structure, instead displaying new and narrower roles at mature synapses where they critically regulate dynamic aspects of synaptic signaling, structural plasticity, and cognitive function. At mature synapses, cadherins are an integral component of multiprotein networks, modifying synaptic signaling, morphology, and plasticity through collaborative interactions with other CAM family members as well as a variety of neurotransmitter receptors, scaffolding proteins, and other effector molecules. Such recognition of the ever-evolving functions of synaptic cadherins may yield insight into the pathophysiology of brain disorders in which cadherins have been implicated and that manifest at different times of life.
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Affiliation(s)
- Lauren G Friedman
- Fishberg Department of Neuroscience, Friedman Brain Institute and the Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Deanna L Benson
- Fishberg Department of Neuroscience, Friedman Brain Institute and the Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, USA
| | - George W Huntley
- Fishberg Department of Neuroscience, Friedman Brain Institute and the Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, USA.
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Liao YW, Wu XM, Jia J, Wu XL, Tao H, Wang HY. Proteolytic antigens interfere with endosome/lysosome fusion in epithelial cells. Biochem Cell Biol 2013; 91:449-54. [PMID: 24219287 DOI: 10.1139/bcb-2012-0115] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The airway epithelial barrier function is important in maintaining the homeostasis in the body. A number of airway disorders are associated with the epithelial barrier dysfunction. The present study aims to elucidate a possible mechanism by which the proteolytic allergens compromise the epithelial barrier function. The airway epithelial cell line, RPMI 2650 cells (Rp cells) and kidney epithelial cell line, MDCK cells, were cultured to be monolayers and used as an in vitro epithelial barrier model. House dust mite antigen, Der P1 (Der) was used as an antigen that has the proteolytic property. The epithelial barrier permeability and transepithelial resistance (TER) were used as the indicators of epithelial barrier function. Both epithelial cell lines could endocytose Der in the culture. Some of the Der was transported across the epithelial barrier to the basal chambers of the Transwells without affecting the TER. The endocytic Der could suppress the expression of ubiquitin E3 lases A20 and further interfered with the fusion of endosome/lysosome in the epithelial cells. Mite antigen, Der, can interfere with the fusion of endosome/lysosome in epithelial cells to induce the epithelial barrier dysfunction.
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Affiliation(s)
- Yu-Wei Liao
- Department of Anesthesiology, Shengjing Hospital, China Medical University, Shenyang, China
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Weiner JA, Jontes JD. Protocadherins, not prototypical: a complex tale of their interactions, expression, and functions. Front Mol Neurosci 2013; 6:4. [PMID: 23515683 PMCID: PMC3601302 DOI: 10.3389/fnmol.2013.00004] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 03/01/2013] [Indexed: 12/30/2022] Open
Abstract
The organization of functional neural circuits requires the precise and coordinated control of cell-cell interactions at nearly all stages of development, including neuronal differentiation, neuronal migration, axon outgrowth, dendrite arborization, and synapse formation and stabilization. This coordination is brought about by the concerted action of a large number of cell surface receptors, whose dynamic regulation enables neurons (and astrocytes) to adopt their proper roles within developing neural circuits. The protocadherins (Pcdhs) comprise a major family of cell surface receptors expressed in the developing vertebrate nervous system whose cellular and developmental roles are only beginning to be elucidated. In this review, we highlight selected recent results in several key areas of Pcdh biology and discuss their implications for our understanding of neural circuit formation and function.
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Affiliation(s)
- Joshua A Weiner
- Department of Biology, The University of Iowa Iowa City, IA, USA
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Dallosso AR, Øster B, Greenhough A, Thorsen K, Curry TJ, Owen C, Hancock AL, Szemes M, Paraskeva C, Frank M, Andersen CL, Malik K. Long-range epigenetic silencing of chromosome 5q31 protocadherins is involved in early and late stages of colorectal tumorigenesis through modulation of oncogenic pathways. Oncogene 2012; 31:4409-19. [PMID: 22249255 DOI: 10.1038/onc.2011.609] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Loss of tumour suppressor gene function can occur as a result of epigenetic silencing of large chromosomal regions, referred to as long-range epigenetic silencing (LRES), and genome-wide analyses have revealed that LRES is present in many cancer types. Here we utilize Illumina Beadchip methylation array analysis to identify LRES across 800 kb of chromosome 5q31 in colorectal adenomas and carcinomas (n=34) relative to normal colonic epithelial DNA (n=6). This region encompasses 53 individual protocadherin (PCDH) genes divided among three gene clusters. Hypermethylation within these gene clusters is asynchronous; while most PCDH hypermethylation occurs early, and is apparent in adenomas, PCDHGC3 promoter methylation occurs later in the adenoma-carcinoma transition. PCDHGC3 was hypermethylated in 17/28 carcinomas (60.7%) according to methylation array analysis. Quantitative real-time reverse transcription-polymerase chain reaction showed that PCDHGC3 is the highest expressed PCDH in normal colonic epithelium, and that there was a strong reciprocal relationship between PCDHGC3 methylation and expression in carcinomas (R=-0.84). PCDH LRES patterns are reflected in colorectal tumour cell lines; adenoma cell lines are not methylated at PCDHGC3 and show abundant expression at the mRNA and protein level, while the expression is suppressed in hypermethylated carcinoma cell lines (R=-0.73). Short-interfering RNA-mediated reduction of PCDHGC3 led to a decrease of apoptosis in RG/C2 adenoma cells, and overexpression of PCDHGC3 in HCT116 cells resulted in the reduction of colony formation, consistent with tumour suppressor capabilities for PCDHGC3. Further functional analysis showed that PCDHGC3 can suppress Wnt and mammalian target of rapamycin signalling in colorectal cancer cell lines. Taken together, our data suggest that the PCDH LRES is an important tumour suppressor locus in colorectal cancer, and that PCDHGC3 may be a strong marker and driver for the adenoma-carcinoma transition.
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Affiliation(s)
- A R Dallosso
- Cancer Epigenetics Laboratory, School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK
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