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Journal of the American Society of... Feb 2017Rho family GTPases, the prototypical members of which are Cdc42, Rac1, and RhoA, are molecular switches best known for regulating the actin cytoskeleton. In addition to...
Rho family GTPases, the prototypical members of which are Cdc42, Rac1, and RhoA, are molecular switches best known for regulating the actin cytoskeleton. In addition to the canonical small GTPases, the large GTPase dynamin has been implicated in regulating the actin cytoskeleton via direct dynamin-actin interactions. The physiologic role of dynamin in regulating the actin cytoskeleton has been linked to the maintenance of the kidney filtration barrier. Additionally, the small molecule Bis-T-23, which promotes actin-dependent dynamin oligomerization and thus, increases actin polymerization, improved renal health in diverse models of CKD, implicating dynamin as a potential therapeutic target for the treatment of CKD. Here, we show that treating cultured mouse podocytes with Bis-T-23 promoted stress fiber formation and focal adhesion maturation in a dynamin-dependent manner. Furthermore, Bis-T-23 induced the formation of focal adhesions and stress fibers in cells in which the RhoA signaling pathway was downregulated by multiple experimental approaches. Our study suggests that dynamin regulates focal adhesion maturation by a mechanism parallel to and synergistic with the RhoA signaling pathway. Identification of dynamin as one of the essential and autonomous regulators of focal adhesion maturation suggests a molecular mechanism that underlies the beneficial effect of Bis-T-23 on podocyte physiology.
Topics: Actin Cytoskeleton; Animals; Dynamins; Focal Adhesions; Mice; Podocytes; Signal Transduction; rhoA GTP-Binding Protein
PubMed: 27432739
DOI: 10.1681/ASN.2016010008 -
Cell Oct 1993Src homology 3 (SH3) domains have been implicated in mediating protein-protein interactions in receptor signaling processes; however, the precise role of this domain... (Comparative Study)
Comparative Study
Src homology 3 (SH3) domains have been implicated in mediating protein-protein interactions in receptor signaling processes; however, the precise role of this domain remains unclear. In this report, affinity purification techniques were used to identify the GTPase dynamin as an SH3 domain-binding protein. Selective binding to a subset of 15 different recombinant SH3 domains occurs through proline-rich sequence motifs similar to those that mediate the interaction of the SH3 domains of Grb2 and Abl proteins to the guanine nucleotide exchange protein, Sos, and to the 3BP1 protein, respectively. Dynamin GTPase activity is stimulated by several of the bound SH3 domains, suggesting that the function of the SH3 module is not restricted to protein-protein interactions but may also include the interactive regulation of GTP-binding proteins.
Topics: Amino Acid Sequence; Animals; Binding Sites; Brain; Drosophila; Dynamins; Enzyme Activation; GTP Phosphohydrolases; Glutathione Transferase; Humans; Kinetics; Mice; Molecular Sequence Data; Rats; Recombinant Fusion Proteins; Recombinant Proteins; Sequence Homology, Amino Acid; Signal Transduction
PubMed: 8402898
DOI: No ID Found -
Cell Calcium May 2022Following calcium-triggered vesicle exocytosis, endocytosis regenerates vesicles to maintain exocytosis and thus synaptic transmission, which underlies neuronal circuit...
Following calcium-triggered vesicle exocytosis, endocytosis regenerates vesicles to maintain exocytosis and thus synaptic transmission, which underlies neuronal circuit activities. Although most molecules involved in endocytosis have been identified, it remains rather poorly understood how endocytic machinery regulates vesicle size. Vesicle size, together with the transmitter concentration inside the vesicle, determines the amount of transmitter the vesicle can release, the quantal size, that may control the strength of synaptic transmission. Here, we report that, surprisingly, knockout of the GTPase dynamin 1, the most abundant brain dynamin isoform known to catalyze fission of the membrane pit's neck (the last step of endocytosis), not only significantly slowed endocytosis but also increased the synaptic vesicle diameter by as much as ∼40-64% at cultured hippocampal synapses. Furthermore, dynamin 1 knockout increased the size of membrane pits, the precursor for endocytic vesicle formation. These results suggest an important function of dynamin other than its well-known fission function - control of vesicle size at the pit formation stage.
Topics: Dynamin I; Dynamins; Endocytosis; Hippocampus; Synapses
PubMed: 35220002
DOI: 10.1016/j.ceca.2022.102564 -
Proceedings of the National Academy of... Aug 2021Pancreatic β cells operate with a high rate of membrane recycling for insulin secretion, yet endocytosis in these cells is not fully understood. We investigate this...
Pancreatic β cells operate with a high rate of membrane recycling for insulin secretion, yet endocytosis in these cells is not fully understood. We investigate this process in mature mouse β cells by genetically deleting dynamin GTPase, the membrane fission machinery essential for clathrin-mediated endocytosis. Unexpectedly, the mice lacking all three dynamin genes (, , ) in their β cells are viable, and their β cells still contain numerous insulin granules. Endocytosis in these β cells is severely impaired, resulting in abnormal endocytic intermediates on the plasma membrane. Although insulin granules are abundant, their release upon glucose stimulation is blunted in both the first and second phases, leading to hyperglycemia and glucose intolerance in mice. Dynamin triple deletion impairs insulin granule exocytosis and decreases intracellular Ca responses and granule docking. The docking defect is correlated with reduced expression of Munc13-1 and RIM1 and reorganization of cortical F-actin in β cells. Collectively, these findings uncover the role of dynamin in dense-core vesicle endocytosis and secretory capacity. Insulin secretion deficiency in the absence of dynamin-mediated endocytosis highlights the risk of impaired membrane trafficking in endocrine failure and diabetes pathogenesis.
Topics: Animals; Blood Glucose; Calcium Signaling; Dense Core Vesicles; Dynamin II; Dynamins; Endocytosis; Female; GTP-Binding Proteins; Hyperglycemia; Insulin Secretion; Insulin-Secreting Cells; Male; Mice, Knockout; Mice, Transgenic; Nerve Tissue Proteins; Mice
PubMed: 34362840
DOI: 10.1073/pnas.2021764118 -
Structure (London, England : 1993) Oct 2012Dynamin is a multidomain mechanochemical guanine triphosphatase that catalyzes membrane scission, most notably of clathrin-coated endocytic vesicles. A number of recent... (Review)
Review
Dynamin is a multidomain mechanochemical guanine triphosphatase that catalyzes membrane scission, most notably of clathrin-coated endocytic vesicles. A number of recent publications have provided structural and mechanistic insights into the formation of helical dynamin filaments assembled by dynamic interactions of multiple domains within dynamin. As a prerequisite for membrane scission, this oligomer undergoes nucleotide-triggered large scale dynamic rearrangements. Here, we review these structural findings and discuss how the architecture of dynamin is poised for the assembly into right-handed helical filaments. Based on these data, we propose a structure-based model for dynamin-mediated scission of membranes.
Topics: Animals; Catalytic Domain; Cell Membrane Structures; Dynamins; Endocytosis; Humans; Models, Molecular; Protein Multimerization; Protein Structure, Quaternary; Protein Structure, Secondary
PubMed: 23063009
DOI: 10.1016/j.str.2012.08.028 -
Current Opinion in Structural Biology Dec 2010Dynamins form a family of eukaryotic and prokaryotic proteins involved in membrane fission, fusion and restructuring. They have complex mechanisms of self-assembly,... (Review)
Review
Dynamins form a family of eukaryotic and prokaryotic proteins involved in membrane fission, fusion and restructuring. They have complex mechanisms of self-assembly, which are coupled to the tubulation and destabilization of lipid bilayers. Recent structural data has revolutionized our understanding and is now yielding detailed insights into dynamin structure, from monomer through to polymer. Traditional division of the dynamin subunit into GTPase domain, middle domain and GTPase effector domain based on sequence alignments and biochemistry is not supported by recent structural data. A unified model of dynamin architecture is presented here, based on observation that the basic dynamin fold is conserved across evolutionary kingdoms.
Topics: Animals; Dynamins; Humans; Membrane Fusion; Protein Multimerization; Protein Structure, Quaternary
PubMed: 20970992
DOI: 10.1016/j.sbi.2010.09.011 -
FEBS Letters Jun 1996The internalization of receptor-bound ligands involves concentration of cell surface receptors in specialized areas of the plasma membrane and subsequent formation of... (Review)
Review
The internalization of receptor-bound ligands involves concentration of cell surface receptors in specialized areas of the plasma membrane and subsequent formation of clathrin-coated vesicles. The complex process of invagination, constriction and budding of clathrin-coated vesicles employs the coordinated actions of several proteins. This review is focused on the GTPase dynamin, which plays a key role in the constriction of coated pits.
Topics: Animals; Dynamins; Endocytosis; GTP Phosphohydrolases; Humans; Receptors, Cell Surface
PubMed: 8682204
DOI: 10.1016/0014-5793(96)00517-0 -
Journal of Bioenergetics and... Feb 2003Nucleoside diphosphate (NDP) kinase is required for multiple cellular functions, including cell growth, motility, and differentiation, and its loss is associated with... (Review)
Review
Nucleoside diphosphate (NDP) kinase is required for multiple cellular functions, including cell growth, motility, and differentiation, and its loss is associated with pathologies including tumor metastasis. A recent study has revealed a previously unknown function for NDP kinase as positive regulator of dynamin, a GTPase essential for endocytosis. In this review we describe the evidence that NDP kinase function is essential for endocytosis and also elaborate on a mechanism for NDP kinase regulation of dynamin. Recently documented interactions between endocytosis and cell signaling have revealed new insights into potential mechanisms of cancer. In this context, we discuss the possible relevance of NDP kinase and dynamin interaction for tumor suppression.
Topics: Animals; Coenzymes; Dynamins; Endocytosis; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Neoplastic; Humans; Models, Biological; Multienzyme Complexes; Neoplasms; Nucleoside-Diphosphate Kinase; Transcriptional Activation
PubMed: 12848341
DOI: 10.1023/a:1023441806530 -
BMC Neuroscience Jun 2009Guanine nucleotide exchange factors (GEFs) and their target Rho GTPases regulate cytoskeletal changes and membrane trafficking. Dynamin, a large force-generating GTPase,...
BACKGROUND
Guanine nucleotide exchange factors (GEFs) and their target Rho GTPases regulate cytoskeletal changes and membrane trafficking. Dynamin, a large force-generating GTPase, plays an essential role in membrane tubulation and fission in cells. Kalirin12, a neuronal RhoGEF, is found in growth cones early in development and in dendritic spines later in development.
RESULTS
The IgFn domain of Kalirin12, not present in other Kalirin isoforms, binds dynamin1 and dynamin2. An inactivating mutation in the GTPase domain of dynamin diminishes this interaction and the isolated GTPase domain of dynamin retains the ability to bind Kalirin12. Co-immunoprecipitation demonstrates an interaction of Kalirin12 and dynamin2 in embryonic brain. Purified recombinant Kalirin-IgFn domain inhibits the ability of purified rat brain dynamin to oligomerize in response to the presence of liposomes containing phosphatidylinositol-4,5-bisphosphate. Consistent with this, expression of exogenous Kalirin12 or its IgFn domain in PC12 cells disrupts clathrin-mediated transferrin endocytosis. Similarly, expression of exogenous Kalirin12 disrupts transferrin endocytosis in cortical neurons. Expression of Kalirin7, a shorter isoform which lacks the IgFn domain, was previously shown to inhibit clathrin-mediated endocytosis; the GTPase domain of dynamin does not interact with Kalirin7.
CONCLUSION
Kalirin12 may play a role in coordinating Rho GTPase-mediated changes in the actin cytoskeleton with dynamin-mediated changes in membrane trafficking.
Topics: Animals; Cells, Cultured; Cerebral Cortex; Clathrin; Dynamins; Embryo, Mammalian; Endocytosis; GTP Phosphohydrolases; Gene Expression; Green Fluorescent Proteins; Growth Cones; Guanine Nucleotide Exchange Factors; Immunoprecipitation; Liposomes; Neurons; Phosphatidylinositol 4,5-Diphosphate; Protein Isoforms; Protein Structure, Tertiary; Rats; Transfection; Transferrin
PubMed: 19534784
DOI: 10.1186/1471-2202-10-61 -
Journal of Cell Science Jul 2013Dynamin is a large multidomain GTPase that assembles into helical arrays around the necks of deeply invaginated clathrin-coated pits and catalyzes membrane fission... (Review)
Review
Dynamin is a large multidomain GTPase that assembles into helical arrays around the necks of deeply invaginated clathrin-coated pits and catalyzes membrane fission during the final stages of endocytosis. Although it is well established that the function of dynamin in vivo depends on its oligomerization and its capacity for efficient GTP hydrolysis, the molecular mechanisms governing these activities have remained poorly defined. In recent years, there has been an explosion of structural data that has provided new insights into the architecture, organization and nucleotide-dependent conformational changes of the dynamin fission machine. Here, we review the key findings of these efforts and discuss the implications of each with regard to GTP hydrolysis, dynamin assembly and membrane fission.
Topics: Animals; Arabidopsis; Clathrin; Coated Pits, Cell-Membrane; Dynamins; Endocytosis; Guanosine Triphosphate; Humans; Hydrolysis; Mitochondrial Dynamics; Models, Molecular; Protein Conformation; Protein Isoforms; Protein Multimerization; Protein Structure, Tertiary
PubMed: 23781021
DOI: 10.1242/jcs.108845