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Sun Y, Men W, Kennerknecht I, Fang W, Zheng HF, Zhang W, Rao Y. Human genetics of face recognition: discovery of MCTP2 mutations in humans with face blindness (congenital prosopagnosia). Genetics 2024; 227:iyae047. [PMID: 38547502 DOI: 10.1093/genetics/iyae047] [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: 12/24/2023] [Accepted: 03/19/2024] [Indexed: 06/06/2024] Open
Abstract
Face recognition is important for both visual and social cognition. While prosopagnosia or face blindness has been known for seven decades and face-specific neurons for half a century, the molecular genetic mechanism is not clear. Here we report results after 17 years of research with classic genetics and modern genomics. From a large family with 18 congenital prosopagnosia (CP) members with obvious difficulties in face recognition in daily life, we uncovered a fully cosegregating private mutation in the MCTP2 gene which encodes a calcium binding transmembrane protein expressed in the brain. After screening through cohorts of 6589, we found more CPs and their families, allowing detection of more CP associated mutations in MCTP2. Face recognition differences were detected between 14 carriers with the frameshift mutation S80fs in MCTP2 and 19 noncarrying volunteers. Six families including one with 10 members showed the S80fs-CP correlation. Functional magnetic resonance imaging found association of impaired recognition of individual faces by MCTP2 mutant CPs with reduced repetition suppression to repeated facial identities in the right fusiform face area. Our results have revealed genetic predisposition of MCTP2 mutations in CP, 76 years after the initial report of prosopagnosia and 47 years after the report of the first CP. This is the first time a gene required for a higher form of visual social cognition was found in humans.
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Affiliation(s)
- Yun Sun
- Chinese Institutes for Medical Research, Capital Medical University, Beijing 100069, China
- Chinese Institute for Brain Research, Peking-Tsinghua Center for Life Sciences, PKU-IDG/McGovern Institute for Brain Research, School of Life Sciences, Peking University, Beijing 100871, China
- Institute of Molecular Physiology, Shenzhen Bay Laboratory, Shenzhen 518107, China
| | - Weiwei Men
- Center for MRI Research, Academy for Advanced Interdisciplinary Studies, Beijing Key Lab for Medical Physics and Engineering, Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871, China
| | - Ingo Kennerknecht
- Institute of Human Genetics, Westfälische Wilhelms-Universität, Münster 48149, Germany
| | - Wan Fang
- Chinese Institute for Brain Research, Peking-Tsinghua Center for Life Sciences, PKU-IDG/McGovern Institute for Brain Research, School of Life Sciences, Peking University, Beijing 100871, China
| | - Hou-Feng Zheng
- School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China
| | - Wenxia Zhang
- Chinese Institutes for Medical Research, Capital Medical University, Beijing 100069, China
- Chinese Institute for Brain Research, Peking-Tsinghua Center for Life Sciences, PKU-IDG/McGovern Institute for Brain Research, School of Life Sciences, Peking University, Beijing 100871, China
| | - Yi Rao
- Chinese Institutes for Medical Research, Capital Medical University, Beijing 100069, China
- Chinese Institute for Brain Research, Peking-Tsinghua Center for Life Sciences, PKU-IDG/McGovern Institute for Brain Research, School of Life Sciences, Peking University, Beijing 100871, China
- Institute of Molecular Physiology, Shenzhen Bay Laboratory, Shenzhen 518107, China
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Espino-Saldaña AE, Durán-Ríos K, Olivares-Hernandez E, Rodríguez-Ortiz R, Arellano-Carbajal F, Martínez-Torres A. Temporal and spatial expression of zebrafish mctp genes and evaluation of frameshift alleles of mctp2b. Gene 2020; 738:144371. [PMID: 32001375 DOI: 10.1016/j.gene.2020.144371] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 01/11/2020] [Accepted: 01/13/2020] [Indexed: 01/28/2023]
Abstract
MCTPs (multiple C2 domain proteins with two transmembrane regions) have been proposed as novel endoplasmic reticulum calcium sensors; however, their function remains largely unknown. Here we report the structure of the four mctp genes from zebrafish (mctp1a, mctp1b, mctp2a and mctp2b), their diversity, expression pattern during embryonic development and in adult tissue and the effect of knocking down the expression of Mctp2b by CRISPR/Cas9. The four mctp genes are expressed from early development and exhibit differential expression patterns but are found mainly in the nervous and muscular systems. Mctp2b tagged with fluorescent proteins and expressed in HEK-293 cells and neurons of the fish spinal cord localized mostly in the endoplasmic reticulum but also in lysosomes and late and recycling endosomes. Knocking down mctp2b expression impaired embryonic development, suggesting that the functional participation of this gene is relevant, at least during the early stages of development.
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Affiliation(s)
- Angeles E Espino-Saldaña
- Instituto de Neurobiología, Universidad Nacional Autónoma de México, Departamento de Neurobiología Celular y Molecular, Laboratorio de Neurobiología Molecular y Celular, Juriquilla, Querétaro, 76230, Mexico; Universidad Autónoma de Querétaro, Facultad de Ciencias Naturales, Av. de las Ciencias S/N, Querétaro, Mexico
| | - Karina Durán-Ríos
- Instituto de Neurobiología, Universidad Nacional Autónoma de México, Departamento de Neurobiología Celular y Molecular, Laboratorio de Neurobiología Molecular y Celular, Juriquilla, Querétaro, 76230, Mexico
| | - Eduardo Olivares-Hernandez
- Instituto de Neurobiología, Universidad Nacional Autónoma de México, Departamento de Neurobiología Celular y Molecular, Laboratorio de Neurobiología Molecular y Celular, Juriquilla, Querétaro, 76230, Mexico
| | - Roberto Rodríguez-Ortiz
- CONACYT- Instituto de Neurobiología, Universidad Nacional Autónoma de México, Departamento de Neurobiología Celular y Molecular, Laboratorio de Neurobiología Molecular y Celular, Juriquilla, Querétaro, 76230, Mexico
| | - Fausto Arellano-Carbajal
- Universidad Autónoma de Querétaro, Facultad de Ciencias Naturales, Av. de las Ciencias S/N, Querétaro, Mexico
| | - Ataulfo Martínez-Torres
- Instituto de Neurobiología, Universidad Nacional Autónoma de México, Departamento de Neurobiología Celular y Molecular, Laboratorio de Neurobiología Molecular y Celular, Juriquilla, Querétaro, 76230, Mexico.
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Brodin L, Shupliakov O. Retromer in Synaptic Function and Pathology. Front Synaptic Neurosci 2018; 10:37. [PMID: 30405388 PMCID: PMC6207580 DOI: 10.3389/fnsyn.2018.00037] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 10/03/2018] [Indexed: 12/15/2022] Open
Abstract
The retromer complex mediates export of select transmembrane proteins from endosomes to the trans-Golgi network (TGN) or to the plasma membrane. Dysfunction of retromer has been linked with slowly progressing neurodegenerative disorders, including Alzheimer’s and Parkinson’s disease (AD and PD). As these disorders affect synapses it is of key importance to clarify the function of retromer-dependent protein trafficking pathways in pre- and postsynaptic compartments. Here we discuss recent insights into the roles of retromer in the trafficking of synaptic vesicle proteins, neurotransmitter receptors and other synaptic proteins. We also consider evidence that implies synapses as sites of early pathology in neurodegenerative disorders, pointing to a possible role of synaptic retromer dysfunction in the initiation of disease.
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Affiliation(s)
- Lennart Brodin
- Department of Neuroscience, Karolinska Institutet (KI), Stockholm, Sweden
| | - Oleg Shupliakov
- Department of Neuroscience, Karolinska Institutet (KI), Stockholm, Sweden.,Institute of Translational Biomedicine, St. Petersburg University, St. Petersburg, Russia
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Binotti B, Jahn R, Chua JJE. Functions of Rab Proteins at Presynaptic Sites. Cells 2016; 5:E7. [PMID: 26861397 PMCID: PMC4810092 DOI: 10.3390/cells5010007] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 02/03/2016] [Indexed: 01/24/2023] Open
Abstract
Presynaptic neurotransmitter release is dominated by the synaptic vesicle (SV) cycle and entails the biogenesis, fusion, recycling, reformation or turnover of synaptic vesicles-a process involving bulk movement of membrane and proteins. As key mediators of membrane trafficking, small GTPases from the Rab family of proteins play critical roles in this process by acting as molecular switches that dynamically interact with and regulate the functions of different sets of macromolecular complexes involved in each stage of the cycle. Importantly, mutations affecting Rabs, and their regulators or effectors have now been identified that are implicated in severe neurological and neurodevelopmental disorders. Here, we summarize the roles and functions of presynaptic Rabs and discuss their involvement in the regulation of presynaptic function.
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Affiliation(s)
- Beyenech Binotti
- Department of Neurobiology, Max-Planck-Institute for Biophysical Chemistry, Göttingen 37077, Germany
| | - Reinhard Jahn
- Department of Neurobiology, Max-Planck-Institute for Biophysical Chemistry, Göttingen 37077, Germany
| | - John Jia En Chua
- Interactomics and Intracellular Trafficking laboratory, Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117456, Singapore.
- Neurobiology/Ageing Programme, National University of Singapore, Singapore 117456, Singapore.
- Research Group Protein trafficking in synaptic development and function, Department of Neurobiology, Max-Planck-Institute for Biophysical Chemistry, Göttingen 37077, Germany.
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Qiu L, Yu H, Liang F. Multiple C2 domains transmembrane protein 1 is expressed in CNS neurons and possibly regulates cellular vesicle retrieval and oxidative stress. J Neurochem 2015. [PMID: 26195140 DOI: 10.1111/jnc.13251] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Multiple C2 domains transmembrane protein 1 (MCTP1) contains two transmembrane regions and three C2 domains of high Ca(2+)-binding affinity. Single-nucleotide polymorphism (SNP) of human MCTP1 gene is reportedly associated with bipolar disorder, but expression and function of MCTP1 in the CNS is still largely unknown. We cloned rat MCTP1 isoforms, and studied expression of MCTP1 transcript and protein in the CNS. Subcellular distribution and functional roles of MCTP1 were investigated in cultured primary neurons or PC12 cells by over-expression, cell imaging, and flow cytometry. MCTP1 immunostaining was seen in both CNS neuronal cell bodies and processes, especially in the hippocampus, dentate gyrus, medial habenular nucleus, amygdala, and selected cerebral and cerebellar cortical areas/layers. Under an electron microscope, MCTP1 immunoreactivity was observed on vesicles in neuronal cell bodies and pre-synaptic axon terminals. In cultured primary neurons and PC12 cells MCTP1 was detected on selected populations of secretory vesicles and endosomes. MCTP1 over-expression significantly inhibited neuronal transferrin endocytosis, secretory vesicle retrieval, cell migration, and oxidative stress from glutamate toxicity. Thus MCTP1 might be involved in regulating endocytic recycling of specific CNS neurons and synapses. MCTP1 abnormality might cause altered synaptic vesicle recycling, and thereby lead to vulnerability to neuropsychiatric diseases.
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Affiliation(s)
- Lifeng Qiu
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Hanry Yu
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Institute of Bioengineering and Nanotechnology, A*STAR, Singapore, Singapore.,Mechanobiology Institute, Singapore, Singapore.,Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Fengyi Liang
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
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Reaction time and replenishment time of SP and CGRP after incision in rat skin. Open Life Sci 2014. [DOI: 10.2478/s11535-014-0349-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractBackground. The skin neurogenic inflammation is mainly related to Substance P (SP) and Calcitonin Gene-related Peptide (CGRP). There is no data on their availability in the dynamics of skin nerve endings, concerning their release and replenishment after a nociceptive stimulus, so this was investigated. Materials and methods. 25 rats were randomly distributed in 5 groups. The animals of the control group (CG) determined the baseline levels of neuropeptides in the skin. The groups S0 and S30 did not receive any cutaneous stimulus at 30 and 60 minutes, respectively. In the group S1, an “incision stimulus” was made at 30 minutes. In the group S31, a nociceptive stimulus was performed by subdermal scratching at 30 minutes and, at 60 minutes, the “incision stimulus” was carried out in the same location (“nociceptive hyperstimulation”). The skin samples of the other animals were harvested from the back 1 minute after their death. SP, pro-CGRP and CGRP were quantified by Western Blotting. Results. The “incision stimulus” released SP, S1 compared to S0 (p <0.05) detected in the first minute, and the replenishment time was more than 30 minutes. Also, it cleaved pro-CGRP, S1 compared to S31 (p <0.05) in the first minute, and its replenishment time less than 30 minutes. Release of CGRP was not detected. Conclusion. The incision released SP already detected in the first minute; its replenishment time is more than 30 minutes. The incision decreased pro-CGRP, also detected in the first minute; and its replenishment time is less than 30 minutes.
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Barth J, Volknandt W. Proteomic investigations of the synaptic vesicle interactome. Expert Rev Proteomics 2014; 8:211-20. [DOI: 10.1586/epr.11.7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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D'Adamo P, Masetti M, Bianchi V, Morè L, Mignogna ML, Giannandrea M, Gatti S. RAB GTPases and RAB-interacting proteins and their role in the control of cognitive functions. Neurosci Biobehav Rev 2014; 46 Pt 2:302-14. [PMID: 24412241 DOI: 10.1016/j.neubiorev.2013.12.009] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Revised: 11/15/2013] [Accepted: 12/16/2013] [Indexed: 12/18/2022]
Abstract
A RAS-related class of small monomeric G proteins, the RAB GTPases, is emerging as of key biological importance in compartment specific directional control of vesicles formation, transport and fusion. Thanks to human genetic observation and to the consequent dedicated biochemical work, substantial progress has been made on the understanding of the role played by RAB GTPases and their effector proteins on neuronal development and the shaping of cognitive functions. This review is highlighting these initial elements to broaden the current scope of research on developmental cognitive deficits and take the point of view of RAB GTPases control on membrane transport in neurons and astrocytes.
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Affiliation(s)
- Patrizia D'Adamo
- Dulbecco Telethon Institute at San Raffaele Scientific Institute, Division of Neuroscience, via Olgettina 58, 20132 Milan, Italy; Vita-Salute San Raffaele University, via Olgettina 58, 20132 Milan, Italy.
| | - Michela Masetti
- Dulbecco Telethon Institute at San Raffaele Scientific Institute, Division of Neuroscience, via Olgettina 58, 20132 Milan, Italy
| | - Veronica Bianchi
- Dulbecco Telethon Institute at San Raffaele Scientific Institute, Division of Neuroscience, via Olgettina 58, 20132 Milan, Italy; Vita-Salute San Raffaele University, via Olgettina 58, 20132 Milan, Italy
| | - Lorenzo Morè
- Dulbecco Telethon Institute at San Raffaele Scientific Institute, Division of Neuroscience, via Olgettina 58, 20132 Milan, Italy
| | - Maria Lidia Mignogna
- Dulbecco Telethon Institute at San Raffaele Scientific Institute, Division of Neuroscience, via Olgettina 58, 20132 Milan, Italy; Vita-Salute San Raffaele University, via Olgettina 58, 20132 Milan, Italy
| | - Maila Giannandrea
- Dulbecco Telethon Institute at San Raffaele Scientific Institute, Division of Neuroscience, via Olgettina 58, 20132 Milan, Italy; F. Hoffmann-La Roche AG, pRED Pharma Research & Early Development, DTA Neuroscience Grenzacherstrasse 124, Basel CH4070, Switzerland
| | - Silvia Gatti
- F. Hoffmann-La Roche AG, pRED Pharma Research & Early Development, DTA Neuroscience Grenzacherstrasse 124, Basel CH4070, Switzerland
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Stewart RS, Teng H, Wilkinson RS. "Late" macroendosomes and acidic endosomes in vertebrate motor nerve terminals. J Comp Neurol 2012; 520:4275-93. [PMID: 22740045 PMCID: PMC4209591 DOI: 10.1002/cne.23176] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Activity at the vertebrate nerve-muscle synapse creates large macroendosomes (MEs) via bulk membrane infolding. Visualized with the endocytic probe FM1-43, most (94%) of the ∼25 MEs/terminal created by brief (30-Hz, 18-second) stimulation dissipate rapidly (∼1 minute) into vesicles. Others, however, remain for hours. Here we study these "late" MEs by using 4D live imaging over a period of ∼1 hour after stimulation. We find that some (51/398 or 13%) disappear spontaneously via exocytosis, releasing their contents into the extracellular milieu. Others (at least 15/1,960 or 1%) fuse or closely associate with a second class of endosomes that take up acidophilic dyes (acidic endosomes [AEs]). AEs are plentiful (∼47/terminal) and exist independent of stimulation. Unlike MEs, which exhibit Brownian motion, AEs exhibit directed motion (average, 83 nm/sec) on microtubules within and among terminal boutons. AEs populate the axon as well, where movement is predominantly retrograde. They share biochemical and immunohistochemical markers (e.g., lysosomal-associated membrane protein [LAMP-1]) with lysosomes. Fusion/association of MEs with AEs suggests a sorting/degradation pathway in nerve terminals wherein the role of AEs is similar to that of lysosomes. Based on our data, we propose that MEs serve as sorting endosomes. Thus their contents, which include plasma membrane proteins, vesicle proteins, and extracellular levels of Ca(2+) , can be targeted either toward the reformation and budding of synaptic vesicles, toward secretion via exocytosis, or toward a degradation process that utilizes AEs either for lysis within the terminal or for transport toward the cell body.
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Affiliation(s)
- Richard S Stewart
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
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Xue L, Zhang Z, McNeil BD, Luo F, Wu XS, Sheng J, Shin W, Wu LG. Voltage-dependent calcium channels at the plasma membrane, but not vesicular channels, couple exocytosis to endocytosis. Cell Rep 2012; 1:632-8. [PMID: 22813738 DOI: 10.1016/j.celrep.2012.04.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Revised: 02/21/2012] [Accepted: 04/11/2012] [Indexed: 01/01/2023] Open
Abstract
Although calcium influx triggers endocytosis at many synapses and non-neuronal secretory cells, the identity of the calcium channel is unclear. The plasma membrane voltage-dependent calcium channel (VDCC) is a candidate, and it was recently proposed that exocytosis transiently inserts vesicular calcium channels at the plasma membrane, thus triggering endocytosis and coupling it to exocytosis, a mechanism suggested to be conserved from sea urchin to human. Here, we report that the vesicular membrane, when inserted into the plasma membrane upon exocytosis, does not generate a calcium current or calcium increase at a mammalian nerve terminal. Instead, VDCCs at the plasma membrane, including the P/Q-type, provide the calcium influx to trigger rapid and slow endocytosis and, thus, couple endocytosis to exocytosis. These findings call for reconsideration of the vesicular calcium channel hypothesis. They are likely to apply to many synapses and non-neuronal cells in which VDCCs control exocytosis, and exocytosis is coupled to endocytosis.
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Affiliation(s)
- Lei Xue
- National Institute of Neurological Disorders and Stroke, Bethesda, MD 20892, USA
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Sigismund S, Confalonieri S, Ciliberto A, Polo S, Scita G, Di Fiore PP. Endocytosis and signaling: cell logistics shape the eukaryotic cell plan. Physiol Rev 2012; 92:273-366. [PMID: 22298658 DOI: 10.1152/physrev.00005.2011] [Citation(s) in RCA: 236] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Our understanding of endocytosis has evolved remarkably in little more than a decade. This is the result not only of advances in our knowledge of its molecular and biological workings, but also of a true paradigm shift in our understanding of what really constitutes endocytosis and of its role in homeostasis. Although endocytosis was initially discovered and studied as a relatively simple process to transport molecules across the plasma membrane, it was subsequently found to be inextricably linked with almost all aspects of cellular signaling. This led to the notion that endocytosis is actually the master organizer of cellular signaling, providing the cell with understandable messages that have been resolved in space and time. In essence, endocytosis provides the communications and supply routes (the logistics) of the cell. Although this may seem revolutionary, it is still likely to be only a small part of the entire story. A wealth of new evidence is uncovering the surprisingly pervasive nature of endocytosis in essentially all aspects of cellular regulation. In addition, many newly discovered functions of endocytic proteins are not immediately interpretable within the classical view of endocytosis. A possible framework, to rationalize all this new knowledge, requires us to "upgrade" our vision of endocytosis. By combining the analysis of biochemical, biological, and evolutionary evidence, we propose herein that endocytosis constitutes one of the major enabling conditions that in the history of life permitted the development of a higher level of organization, leading to the actuation of the eukaryotic cell plan.
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Affiliation(s)
- Sara Sigismund
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Milan, Italy
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Johnsson AK, Karlsson R. Synaptotagmin 1 causes phosphatidyl inositol lipid-dependent actin remodeling in cultured non-neuronal and neuronal cells. Exp Cell Res 2011; 318:114-26. [PMID: 22036579 DOI: 10.1016/j.yexcr.2011.10.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Revised: 10/04/2011] [Accepted: 10/06/2011] [Indexed: 11/24/2022]
Abstract
Here we demonstrate that a dramatic actin polymerizing activity caused by ectopic expression of the synaptic vesicle protein synaptotagmin 1 that results in extensive filopodia formation is due to the presence of a lysine rich sequence motif immediately at the cytoplasmic side of the transmembrane domain of the protein. This polybasic sequence interacts with anionic phospholipids in vitro, and, consequently, the actin remodeling caused by this sequence is interfered with by expression of a phosphatidyl inositol (4,5)-bisphosphate (PIP2)-targeted phosphatase, suggesting that it intervenes with the function of PIP2-binding actin control proteins. The activity drastically alters the behavior of a range of cultured cells including the neuroblastoma cell line SH-SY5Y and primary cortical mouse neurons, and, since the sequence is conserved also in synaptotagmin 2, it may reflect an important fine-tuning role for these two proteins during synaptic vesicle fusion and neurotransmitter release.
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Affiliation(s)
- Anna-Karin Johnsson
- Department of Cell Biology, Wenner-Gren Institute, Stockholm University, SE-106 91 Stockholm, Sweden
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Takaichi R, Odagaki SI, Kumanogoh H, Nakamura S, Morita M, Maekawa S. Inhibitory effect of NAP-22 on the phosphatase activity of synaptojanin-1. J Neurosci Res 2011; 90:21-7. [DOI: 10.1002/jnr.22740] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2011] [Revised: 05/27/2011] [Accepted: 06/20/2011] [Indexed: 01/28/2023]
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Synaptic vesicle-like lipidome of human cytomegalovirus virions reveals a role for SNARE machinery in virion egress. Proc Natl Acad Sci U S A 2011; 108:12869-74. [PMID: 21768361 DOI: 10.1073/pnas.1109796108] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Human cytomegalovirus induces and requires fatty acid synthesis. This suggests an essential role for lipidome remodeling in viral replication. We used mass spectrometry to quantify glycerophospholipids in mock-infected and virus-infected fibroblasts, as well as in virions. Although the lipid composition of mock-infected and virus-infected fibroblasts was similar, virions were markedly different. The virion envelope contained twofold more phosphatidylethanolamines and threefold less phosphatidylserines than the host cell. This indicates that the virus buds from a membrane with a different lipid composition from the host cell as a whole. Compared with published datasets, the virion envelope showed the greatest similarity to the synaptic vesicle lipidome. Synaptosome-associated protein of 25 kDa (SNAP-25) is a component of the complex that mediates exocytosis of synaptic vesicles in neurons; and its homolog, SNAP-23, functions in exocytosis in many other cell types. Infection induced the relocation of SNAP-23 to the cytoplasmic viral assembly zone, and knockdown of SNAP-23 inhibited the production of virus. We propose that cytomegalovirus capsids acquire their envelope by budding into vesicles with a lipid composition similar to that of synaptic vesicles, which subsequently fuse with the plasma membrane to release virions from the cell.
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The DISABLED protein functions in CLATHRIN-mediated synaptic vesicle endocytosis and exoendocytic coupling at the active zone. Proc Natl Acad Sci U S A 2011; 108:E222-9. [PMID: 21606364 DOI: 10.1073/pnas.1102231108] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Members of the DISABLED (DAB) family of proteins are known to play a conserved role in endocytic trafficking of cell surface receptors by functioning as monomeric CLATHRIN-associated sorting proteins that recruit cargo proteins into endocytic vesicles. Here, we report a Drosophila disabled mutant revealing a novel role for DAB proteins in chemical synaptic transmission. This mutant exhibits impaired synaptic function, including a rapid activity-dependent reduction in neurotransmitter release and disruption of synaptic vesicle endocytosis. In presynaptic boutons, Drosophila DAB and CLATHRIN were highly colocalized within two distinct classes of puncta, including relatively dim puncta that were located at active zones and may reflect endocytic mechanisms operating at neurotransmitter release sites. Finally, broader analysis of endocytic proteins, including DYNAMIN, supported a general role for CLATHRIN-mediated endocytic mechanisms in rapid clearance of neurotransmitter release sites for subsequent vesicle priming and refilling of the release-ready vesicle pool.
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