1
|
Tsong H, Holzbaur ELF, Stavoe AKH. Aging Differentially Affects Axonal Autophagosome Formation and Maturation. Autophagy 2023; 19:3079-3095. [PMID: 37464898 PMCID: PMC10621248 DOI: 10.1080/15548627.2023.2236485] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 06/21/2023] [Accepted: 07/03/2023] [Indexed: 07/20/2023] Open
Abstract
Misregulation of neuronal macroautophagy/autophagy has been implicated in age-related neurodegenerative diseases. We compared autophagosome formation and maturation in primary murine neurons during development and through aging to elucidate how aging affects neuronal autophagy. We observed an age-related decrease in the rate of autophagosome formation leading to a significant decrease in the density of autophagosomes along the axon. Next, we identified a surprising increase in the maturation of autophagic vesicles in neurons from aged mice. While we did not detect notable changes in endolysosomal content in the distal axon during early aging, we did observe a significant loss of acidified vesicles in the distal axon during late aging. Interestingly, we found that autophagic vesicles were transported more efficiently in neurons from adult mice than in neurons from young mice. This efficient transport of autophagic vesicles in both the distal and proximal axon is maintained in neurons during early aging, but is lost during late aging. Our data indicate that early aging does not negatively impact autophagic vesicle transport nor the later stages of autophagy. However, alterations in autophagic vesicle transport efficiency during late aging reveal that aging differentially impacts distinct aspects of neuronal autophagy.Abbreviations: ACAP3: ArfGAP with coiled-coil, ankyrin repeat and PH domains 3; ARF6: ADP-ribosylation factor 6; ATG: autophagy related; AVs: autophagic vesicles; DCTN1/p150Glued: dynactin 1; DRG: dorsal root ganglia; GAP: GTPase activating protein; GEF: guanine nucleotide exchange factor; LAMP2: lysosomal-associated protein 2; LysoT: LysoTracker; MAP1LC3B/LC3B: microtubule-associated protein 1 light chain 3 beta; MAPK8IP1/JIP1: mitogen-activated protein kinase 8 interacting protein 1; MAPK8IP3/JIP3: mitogen-activated protein kinase 8 interacting protein 3; mCh: mCherry; PE: phosphatidylethanolamine.
Collapse
Affiliation(s)
- Heather Tsong
- Department of Neurobiology & Anatomy, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Erika LF Holzbaur
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Andrea KH Stavoe
- Department of Neurobiology & Anatomy, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, USA
| |
Collapse
|
2
|
Timalsina B, Choi HJ, Moon IS. N-Acetylglucosamine Kinase-Small Nuclear Ribonucleoprotein Polypeptide N Interaction Promotes Axodendritic Branching in Neurons via Dynein-Mediated Microtubule Transport. Int J Mol Sci 2023; 24:11672. [PMID: 37511433 PMCID: PMC10380243 DOI: 10.3390/ijms241411672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 07/17/2023] [Accepted: 07/18/2023] [Indexed: 07/30/2023] Open
Abstract
N-acetylglucosamine kinase (NAGK) has been identified as an anchor protein that facilitates neurodevelopment with its non-canonical structural role. Similarly, small nuclear ribonucleoprotein polypeptide N (SNRPN) regulates neurodevelopment and cognitive ability. In our previous study, we revealed the interaction between NAGK and SNRPN in the neuron. However, the precise role in neurodevelopment is elusive. In this study, we investigate the role of NAGK and SNRPN in the axodendritic development of neurons. NAGK and SNRPN interaction is significantly increased in neurons at the crucial stages of neurodevelopment. Furthermore, overexpression of the NAGK and SNRPN proteins increases axodendritic branching and neuronal complexity, whereas the knockdown inhibits neurodevelopment. We also observe the interaction of NAGK and SNRPN with the dynein light-chain roadblock type 1 (DYNLRB1) protein variably during neurodevelopment, revealing the microtubule-associated delivery of the complex. Interestingly, NAGK and SNRPN proteins rescued impaired axodendritic development in an SNRPN depletion model of Prader-Willi syndrome (PWS) patient-derived induced pluripotent stem cell neurons. Taken together, these findings are crucial in developing therapeutic approaches for neurodegenerative diseases.
Collapse
Affiliation(s)
- Binod Timalsina
- Department of Anatomy, Dongguk University College of Medicine, Gyeongju 38066, Republic of Korea
| | - Ho Jin Choi
- Department of Anatomy, Dongguk University College of Medicine, Gyeongju 38066, Republic of Korea
| | - Il Soo Moon
- Department of Anatomy, Dongguk University College of Medicine, Gyeongju 38066, Republic of Korea
| |
Collapse
|
3
|
Abstract
The systematic variation of diameters in branched networks has tantalized biologists since the discovery of da Vinci's rule for trees. Da Vinci's rule can be formulated as a power law with exponent two: The square of the mother branch's diameter is equal to the sum of the squares of those of the daughters. Power laws, with different exponents, have been proposed for branching in circulatory systems (Murray's law with exponent 3) and in neurons (Rall's law with exponent 3/2). The laws have been derived theoretically, based on optimality arguments, but, for the most part, have not been tested rigorously. Using superresolution methods to measure the diameters of dendrites in highly branched Drosophila class IV sensory neurons, we have found that these types of power laws do not hold. In their place, we have discovered a different diameter-scaling law: The cross-sectional area is proportional to the number of dendrite tips supported by the branch plus a constant, corresponding to a minimum diameter of the terminal dendrites. The area proportionality accords with a requirement for microtubules to transport materials and nutrients for dendrite tip growth. The minimum diameter may be set by the force, on the order of a few piconewtons, required to bend membrane into the highly curved surfaces of terminal dendrites. Because the observed scaling differs from Rall's law, we propose that cell biological constraints, such as intracellular transport and protrusive forces generated by the cytoskeleton, are important in determining the branched morphology of these cells.
Collapse
Affiliation(s)
- Maijia Liao
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520
| | - Xin Liang
- Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Jonathon Howard
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520;
| |
Collapse
|
4
|
Cross JA, Chegkazi MS, Steiner RA, Woolfson DN, Dodding MP. Fragment-linking peptide design yields a high-affinity ligand for microtubule-based transport. Cell Chem Biol 2021:S2451-9456(21)00149-5. [PMID: 33838110 DOI: 10.1016/j.chembiol.2021.03.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 02/08/2021] [Accepted: 03/17/2021] [Indexed: 01/05/2023]
Abstract
Synthetic peptides are attractive candidates to manipulate protein-protein interactions inside the cell as they mimic natural interactions to compete for binding. However, protein-peptide interactions are often dynamic and weak. A challenge is to design peptides that make improved interactions with the target. Here, we devise a fragment-linking strategy-"mash-up" design-to deliver a high-affinity ligand, KinTag, for the kinesin-1 motor. Using structural insights from natural micromolar-affinity cargo-adaptor ligands, we have identified and combined key binding features in a single, high-affinity ligand. An X-ray crystal structure demonstrates interactions as designed and reveals only a modest increase in interface area. Moreover, when genetically encoded, KinTag promotes transport of lysosomes with higher efficiency than natural sequences, revealing a direct link between motor-adaptor binding affinity and organelle transport. Together, these data demonstrate a fragment-linking strategy for peptide design and its application in a synthetic motor ligand to direct cellular cargo transport.
Collapse
|
5
|
Duellberg C, Auer A, Canigova N, Loibl K, Loose M. In vitro reconstitution reveals phosphoinositides as cargo-release factors and activators of the ARF6 GAP ADAP1. Proc Natl Acad Sci U S A 2021; 118. [PMID: 33443153 DOI: 10.1073/pnas.2010054118] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The differentiation of cells depends on a precise control of their internal organization, which is the result of a complex dynamic interplay between the cytoskeleton, molecular motors, signaling molecules, and membranes. For example, in the developing neuron, the protein ADAP1 (ADP-ribosylation factor GTPase-activating protein [ArfGAP] with dual pleckstrin homology [PH] domains 1) has been suggested to control dendrite branching by regulating the small GTPase ARF6. Together with the motor protein KIF13B, ADAP1 is also thought to mediate delivery of the second messenger phosphatidylinositol (3,4,5)-trisphosphate (PIP3) to the axon tip, thus contributing to PIP3 polarity. However, what defines the function of ADAP1 and how its different roles are coordinated are still not clear. Here, we studied ADAP1's functions using in vitro reconstitutions. We found that KIF13B transports ADAP1 along microtubules, but that PIP3 as well as PI(3,4)P2 act as stop signals for this transport instead of being transported. We also demonstrate that these phosphoinositides activate ADAP1's enzymatic activity to catalyze GTP hydrolysis by ARF6. Together, our results support a model for the cellular function of ADAP1, where KIF13B transports ADAP1 until it encounters high PIP3/PI(3,4)P2 concentrations in the plasma membrane. Here, ADAP1 disassociates from the motor to inactivate ARF6, promoting dendrite branching.
Collapse
|
6
|
Eberhardt EL, Ludlam AV, Tan Z, Cianfrocco MA. Miro: A molecular switch at the center of mitochondrial regulation. Protein Sci 2020; 29:1269-1284. [PMID: 32056317 DOI: 10.1002/pro.3839] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 02/03/2020] [Accepted: 02/06/2020] [Indexed: 12/24/2022]
Abstract
The orchestration of mitochondria within the cell represents a critical aspect of cell biology. At the center of this process is the outer mitochondrial membrane protein, Miro. Miro coordinates diverse cellular processes by regulating connections between organelles and the cytoskeleton that range from mediating contacts between the endoplasmic reticulum and mitochondria to the regulation of both actin and microtubule motor proteins. Recently, a number of cell biological, biochemical, and protein structure studies have helped to characterize the myriad roles played by Miro. In addition to answering questions regarding Miro's function, these studies have opened the door to new avenues in the study of Miro in the cell. This review will focus on summarizing recent findings for Miro's structure, function, and activity while highlighting key questions that remain unanswered.
Collapse
Affiliation(s)
- Emily L Eberhardt
- Life Sciences Institute, Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, Michigan
| | - Anthony V Ludlam
- Life Sciences Institute, Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan
| | - Zhenyu Tan
- Life Sciences Institute, Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan
- Biophysics Program, University of Michigan, Ann Arbor, Michigan
| | - Michael A Cianfrocco
- Life Sciences Institute, Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan
| |
Collapse
|
7
|
Rao AN, Patil A, Black MM, Craig EM, Myers KA, Yeung HT, Baas PW. Cytoplasmic Dynein Transports Axonal Microtubules in a Polarity-Sorting Manner. Cell Rep 2018; 19:2210-2219. [PMID: 28614709 DOI: 10.1016/j.celrep.2017.05.064] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 04/20/2017] [Accepted: 05/18/2017] [Indexed: 01/20/2023] Open
Abstract
Axonal microtubules are predominantly organized into a plus-end-out pattern. Here, we tested both experimentally and with computational modeling whether a motor-based polarity-sorting mechanism can explain this microtubule pattern. The posited mechanism centers on cytoplasmic dynein transporting plus-end-out and minus-end-out microtubules into and out of the axon, respectively. When cytoplasmic dynein was acutely inhibited, the bi-directional transport of microtubules in the axon was disrupted in both directions, after which minus-end-out microtubules accumulated in the axon over time. Computational modeling revealed that dynein-mediated transport of microtubules can establish and preserve a predominantly plus-end-out microtubule pattern as per the details of the experimental findings, but only if a kinesin motor and a static cross-linker protein are also at play. Consistent with the predictions of the model, partial depletion of TRIM46, a protein that cross-links axonal microtubules in a manner that influences their polarity orientation, leads to an increase in microtubule transport.
Collapse
Affiliation(s)
- Anand N Rao
- Department of Neurobiology and Anatomy, Drexel University, Philadelphia, PA 19129, USA
| | - Ankita Patil
- Department of Neurobiology and Anatomy, Drexel University, Philadelphia, PA 19129, USA
| | - Mark M Black
- Department of Anatomy and Cell Biology, Temple University, Philadelphia, PA 19140, USA
| | - Erin M Craig
- Department of Physics, Central Washington University, Ellensburg, WA 98926, USA
| | - Kenneth A Myers
- Department Biological Sciences, University of the Sciences, Philadelphia, PA 19104, USA
| | - Howard T Yeung
- Department of Physics, Central Washington University, Ellensburg, WA 98926, USA
| | - Peter W Baas
- Department of Neurobiology and Anatomy, Drexel University, Philadelphia, PA 19129, USA.
| |
Collapse
|
8
|
Abstract
mRNA (mRNA) transport focuses the expression of encoded proteins to specific regions within cells providing them with the means to assume specific functions and even identities. BicD and the mRNA binding protein Egl interact with the microtubule motor dynein to localize mRNAs in Drosophila. Because relatively few mRNA cargos were known, we isolated and identified Egl::GFP associated mRNAs. The top candidates were validated by qPCR, in situ hybridization and genetically by showing that their localization requires BicD. In young embryos these Egl target mRNAs are preferentially localized apically, between the plasma membrane and the blastoderm nuclei, but also in the pole plasm at the posterior pole. Egl targets expressed in the ovary were mostly enriched in the oocyte and some were apically localized in follicle cells. The identification of a large group of novel mRNAs associated with BicD/Egl points to several novel developmental and physiological functions of this dynein dependent localization machinery. The verified dataset also allowed us to develop a tool that predicts conserved A'-form-like stem loops that serve as localization elements in 3′UTRs.
Collapse
Affiliation(s)
| | - Bogdan Schaller
- a Institute of Cell Biology, University of Bern , Bern , Switzerland
| | - Martino Colombo
- b Interfaculty Bioinformatics Unit and Swiss Institute of Bioinformatics, University of Bern , Bern , Switzerland.,c Department of Chemistry and Biochemistry , University of Bern , Bern , Switzerland
| | - Dirk Beuchle
- a Institute of Cell Biology, University of Bern , Bern , Switzerland
| | - Samuel Neuenschwander
- b Interfaculty Bioinformatics Unit and Swiss Institute of Bioinformatics, University of Bern , Bern , Switzerland.,d Vital-IT, Swiss Institute of Bioinformatics , Lausanne , Switzerland
| | - Anne Marcil
- e National Research Council Canada, Human Health Therapeutics Portfolio, Building Montréal - Royalmount , Montreal , Quebec , Canada
| | - Rémy Bruggmann
- b Interfaculty Bioinformatics Unit and Swiss Institute of Bioinformatics, University of Bern , Bern , Switzerland
| | - Beat Suter
- a Institute of Cell Biology, University of Bern , Bern , Switzerland
| |
Collapse
|
9
|
Abstract
Which mitochondria are inherited across generations? Are transmitted mitochondria functionally silenced to preserve the integrity of their genetic information, or rather are those mitochondria with the highest levels of function (as indicated by membrane potential Δψm) preferentially transmitted? Based on observations of the unusual system of doubly uniparental inheritance of mitochondria and of the common strictly maternal inheritance mode, I formulate a general hypothesis to explain which mitochondria reach the primordial germ cells (PGCs), and how this happens. Several studies indicate that mitochondrial movements are driven by microtubules and that mitochondria with high Δψm are preferentially transported. This can be applied also to the mitochondria that eventually populate embryonic PGCs, so I propose that Δψm may be a trait that allows for the preferential transmission of the most active (and healthy) mitochondria. The topics discussed here are fundamental in cell biology and genetics but remain controversial and a subject of heated debate; I propose an explanation for how a Δψm-dependent mechanism can cause the observed differences in mitochondrial transmission.
Collapse
Affiliation(s)
- Liliana Milani
- Department of Biological, Geological and Environmental Sciences, University of Bologna, Bologna, Italy
| |
Collapse
|
10
|
Slaughter T, Wang J, Black MM. Microtubule transport from the cell body into the axons of growing neurons. J Neurosci 1997; 17:5807-19. [PMID: 9221779 PMCID: PMC6573214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The present studies test the hypothesis that microtubules (MTs) are transported from the cell body into the axons of growing neurons. Dissociated sympathetic neurons were cultured using conditions that allow us to control the initiation of axon outgrowth. Neurons were injected with biotin-labeled tubulin (Bt-tub) and then stimulated to extend axons. The newly formed axons were then examined using immunofluorescence procedures for MTs with or without Bt-tub. Because the Bt-tub is fully assembly competent, all MTs that assemble after injection will contain Bt-tub. However, MTs that exist in the neuron at the time of injection and persist during the subsequent incubation will not contain Bt-tub. Because the neurons were injected before extending axons, MTs without Bt-tub are initially localized to the cell body. We specifically determined whether these MTs appeared in the newly formed axon. Such a result can only be explained by the transport of these MTs from their initial location in the cell body into the axon. The newly formed axons of many neurons contained MTs both with and without Bt-tub. MTs without Bt-tub were detected all along the axon and in some neurons represented a substantial portion of the total polymer in the proximal and middle regions of the axon. These results show that MTs are transported from the cell body into growing axons and that this transport is robust, delivering MTs to all regions of the newly formed axon.
Collapse
Affiliation(s)
- T Slaughter
- Department of Anatomy and Cell Biology, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA
| | | | | |
Collapse
|