scholarly journals The adhesion-GPCR BAI1 shapes dendritic arbors via Bcr-mediated RhoA activation causing late growth arrest

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Joseph G Duman ◽  
Shalaka Mulherkar ◽  
Yen-Kuei Tu ◽  
Kelly C Erikson ◽  
Christopher P Tzeng ◽  
...  
Keyword(s):  
Hippocampal Neurons ◽  
Rho Gtpase ◽  
Regulatory Protein ◽  
Growth Arrest ◽  
Dendritic Morphology ◽  
Small Gtpase ◽  
Rhoa Activation ◽  
Dependent Growth ◽  
And Function ◽  
Adhesion Gpcr

Dendritic arbor architecture profoundly impacts neuronal connectivity and function, and aberrant dendritic morphology characterizes neuropsychiatric disorders. Here, we identify the adhesion-GPCR BAI1 as an important regulator of dendritic arborization. BAI1 loss from mouse or rat hippocampal neurons causes dendritic hypertrophy, whereas BAI1 overexpression precipitates dendrite retraction. These defects specifically manifest as dendrites transition from growth to stability. BAI1-mediated growth arrest is independent of its Rac1-dependent synaptogenic function. Instead, BAI1 couples to the small GTPase RhoA, driving late RhoA activation in dendrites coincident with growth arrest. BAI1 loss lowers RhoA activation and uncouples it from dendrite dynamics, causing overgrowth. None of BAI1’s known downstream effectors mediates BAI1-dependent growth arrest. Rather, BAI1 associates with the Rho-GTPase regulatory protein Bcr late in development and stimulates its cryptic RhoA-GEF activity, which functions together with its Rac1-GAP activity to terminate arborization. Our results reveal a late-acting signaling pathway mediating a key transition in dendrite development.

scholarly journals Author response: The adhesion-GPCR BAI1 shapes dendritic arbors via Bcr-mediated RhoA activation causing late growth arrest

2019 ◽  
Author(s):  
Joseph G Duman ◽  
Shalaka Mulherkar ◽  
Yen-Kuei Tu ◽  
Kelly C Erikson ◽  
Christopher P Tzeng ◽  
...  
Keyword(s):  
Growth Arrest ◽  
Author Response ◽  
Rhoa Activation ◽  
Dendritic Arbors ◽  
Adhesion Gpcr ◽  
Late Growth

scholarly journals Rho and Anillin-dependent Control of mDia2 Localization and Function in Cytokinesis

2010 ◽  
Vol 21 (18) ◽  
pp. 3193-3204 ◽  
Author(s):  
Sadanori Watanabe ◽  
Katsuya Okawa ◽  
Takashi Miki ◽  
Satoko Sakamoto ◽  
Tomoko Morinaga ◽  
...  
Keyword(s):  
Rna Interference ◽  
Rho Gtpase ◽  
Small Gtpase ◽  
Cleavage Furrow ◽  
3T3 Cells ◽  
Actin Nucleation ◽  
Inhibitory Domain ◽  
And Function ◽  
Rho Effectors ◽  
Nih 3T3

Diaphanous-related formin, mDia, is an actin nucleation/polymerization factor functioning downstream of the small GTPase Rho. Although Rho is critically involved in cytokinesis, it remains elusive how Rho effectors and other regulators of cytoskeletons work together to accomplish this process. Here we focused on mDia2, an mDia isoform involved in cytokinesis of NIH 3T3 cells, and analyzed mechanisms of its localization in cytokinesis. We found that targeting of mDia2 to the cleavage furrow requires not only its binding to RhoA but also its diaphanous-inhibitory domain (DID). We then performed pulldown assays using a fragment containing the latter domain as a bait and identified anillin as a novel mDia2 interaction partner. The anillin-binding is competitive with the diaphanous autoregulatory domain (DAD) of mDia2 in its autoinhibitory interaction. A series of RNA interference and functional rescue experiments has revealed that, in addition to the Rho GTPase-mediated activation, the interaction between mDia2 and anillin is required for the localization and function of mDia2 in cytokinesis.

scholarly journals Protein transport to the dendritic plasma membrane of cultured neurons is regulated by rab8p.

1993 ◽  
Vol 123 (1) ◽  
pp. 47-55 ◽  
Author(s):  
L A Huber ◽  
M J de Hoop ◽  
P Dupree ◽  
M Zerial ◽  
K Simons ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Hippocampal Neurons ◽  
Protein Transport ◽  
Semliki Forest Virus ◽  
Companion Paper ◽  
Small Gtpase ◽  
Cultured Neurons ◽  
Double Labeling ◽  
Basolateral Plasma Membrane ◽  
And Function

In the companion paper (Huber, L. A., S. W. Pimplikar, R. G. Parton, H. Virta, M. Zerial, and K. Simons. J. Cell Biol. 123:35-45) we reported that the small GTPase rab8p is involved in transport from the TGN to the basolateral plasma membrane in epithelia. In the present work we investigated the localization and function of rab8p in polarized hippocampal neurons. By immunofluorescence microscopy we found that rab8p localized preferentially in the somatodendritic domain, and was excluded from the axon. Double-labeling immunofluorescence showed that some of the rab8p co-localized in the dendrites with the Semliki Forest Virus glycoprotein E2 (SFV-E2). An antisense oligonucleotide approach was used to investigate the role of rab8p in dendritic transport of newly synthesized viral glycoproteins. Antisense oligonucleotides corresponding to the initiation region of the rab8 coding sequence were added to the cultured neurons for four days. This treatment resulted in a significant decrease in cellular levels of rab8p and transport of SFV-E2 from the cell body to the dendrites was significantly reduced. However, no effect was observed on axonal transport of influenza HA. From these results we conclude that rab8p is involved in transport of proteins to the dendritic surface in neurons.

TBC proteins: GAPs for mammalian small GTPase Rab?

2011 ◽  
Vol 31 (3) ◽  
pp. 159-168 ◽  
Author(s):  
Mitsunori Fukuda
Keyword(s):  
Insulin Resistance ◽  
Small Gtpases ◽  
Structure And Function ◽  
Small Gtpase ◽  
Cell Cycle Regulators ◽  
Gtpase Activating Protein ◽  
Domain Family ◽  
Protein Motif ◽  
Conserved Domain ◽  
And Function

The TBC (Tre-2/Bub2/Cdc16) domain was originally identified as a conserved domain among the tre-2 oncogene product and the yeast cell cycle regulators Bub2 and Cdc16, and it is now widely recognized as a conserved protein motif that consists of approx. 200 amino acids in all eukaryotes. Since the TBC domain of yeast Gyps [GAP (GTPase-activating protein) for Ypt proteins] has been shown to function as a GAP domain for small GTPase Ypt/Rab, TBC domain-containing proteins (TBC proteins) in other species are also expected to function as a certain Rab-GAP. More than 40 different TBC proteins are present in humans and mice, and recent accumulating evidence has indicated that certain mammalian TBC proteins actually function as a specific Rab-GAP. Some mammalian TBC proteins {e.g. TBC1D1 [TBC (Tre-2/Bub2/Cdc16) domain family, member 1] and TBC1D4/AS160 (Akt substrate of 160 kDa)} play an important role in homoeostasis in mammals, and defects in them are directly associated with mouse and human diseases (e.g. leanness in mice and insulin resistance in humans). The present study reviews the structure and function of mammalian TBC proteins, especially in relation to Rab small GTPases.

scholarly journals PKC-phosphorylation of Liprin-α3 triggers phase separation and controls presynaptic active zone structure

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Javier Emperador-Melero ◽  
Man Yan Wong ◽  
Shan Shan H. Wang ◽  
Giovanni de Nola ◽  
Hajnalka Nyitrai ◽  
...  
Keyword(s):  
Phase Separation ◽  
Active Zone ◽  
Neurotransmitter Release ◽  
Hippocampal Neurons ◽  
Phosphorylation Site ◽  
Double Knockout ◽  
Zone Structure ◽  
Presynaptic Nerve Terminal ◽  
Condensate Formation ◽  
And Function

AbstractThe active zone of a presynaptic nerve terminal defines sites for neurotransmitter release. Its protein machinery may be organized through liquid–liquid phase separation, a mechanism for the formation of membrane-less subcellular compartments. Here, we show that the active zone protein Liprin-α3 rapidly and reversibly undergoes phase separation in transfected HEK293T cells. Condensate formation is triggered by Liprin-α3 PKC-phosphorylation at serine-760, and RIM and Munc13 are co-recruited into membrane-attached condensates. Phospho-specific antibodies establish phosphorylation of Liprin-α3 serine-760 in transfected cells and mouse brain tissue. In primary hippocampal neurons of newly generated Liprin-α2/α3 double knockout mice, synaptic levels of RIM and Munc13 are reduced and the pool of releasable vesicles is decreased. Re-expression of Liprin-α3 restored these presynaptic defects, while mutating the Liprin-α3 phosphorylation site to abolish phase condensation prevented this rescue. Finally, PKC activation in these neurons acutely increased RIM, Munc13 and neurotransmitter release, which depended on the presence of phosphorylatable Liprin-α3. Our findings indicate that PKC-mediated phosphorylation of Liprin-α3 triggers its phase separation and modulates active zone structure and function.

scholarly journals The Ncoa7 locus regulates V-ATPase formation and function, neurodevelopment and behaviour

2020 ◽  
Author(s):  
Enrico Castroflorio ◽  
Joery den Hoed ◽  
Daria Svistunova ◽  
Mattéa J. Finelli ◽  
Alberto Cebrian-Serrano ◽  
...  
Keyword(s):  
Neurodevelopmental Disorders ◽  
Regulatory Protein ◽  
Molecular Function ◽  
Neuronal Connectivity ◽  
Nuclear Receptor Coactivator ◽  
Lysm Domain ◽  
Behavioural Assessment ◽  
And Function ◽  
The Brain

Abstract Members of the Tre2/Bub2/Cdc16 (TBC), lysin motif (LysM), domain catalytic (TLDc) protein family are associated with multiple neurodevelopmental disorders, although their exact roles in disease remain unclear. For example, nuclear receptor coactivator 7 (NCOA7) has been associated with autism, although almost nothing is known regarding the mode-of-action of this TLDc protein in the nervous system. Here we investigated the molecular function of NCOA7 in neurons and generated a novel mouse model to determine the consequences of deleting this locus in vivo. We show that NCOA7 interacts with the cytoplasmic domain of the vacuolar (V)-ATPase in the brain and demonstrate that this protein is required for normal assembly and activity of this critical proton pump. Neurons lacking Ncoa7 exhibit altered development alongside defective lysosomal formation and function; accordingly, Ncoa7 deletion animals exhibited abnormal neuronal patterning defects and a reduced expression of lysosomal markers. Furthermore, behavioural assessment revealed anxiety and social defects in mice lacking Ncoa7. In summary, we demonstrate that NCOA7 is an important V-ATPase regulatory protein in the brain, modulating lysosomal function, neuronal connectivity and behaviour; thus our study reveals a molecular mechanism controlling endolysosomal homeostasis that is essential for neurodevelopment. Graphic abstract

scholarly journals Adenovirus E4orf4 protein induces PP2A-dependent growth arrest in Saccharomyces cerevisiae and interacts with the anaphase-promoting complex/cyclosome

2001 ◽  
Vol 154 (2) ◽  
pp. 331-344 ◽  
Author(s):  
Daniel Kornitzer ◽  
Rakefet Sharf ◽  
Tamar Kleinberger
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Mammalian Cells ◽  
Growth Arrest ◽  
Anaphase Promoting Complex ◽  
Reading Frame ◽  
Cycle Growth ◽  
M Phase ◽  
Dependent Growth ◽  
Synthetically Lethal

Adenovirus early region 4 open reading frame 4 (E4orf4) protein has been reported to induce p53-independent, protein phosphatase 2A (PP2A)–dependent apoptosis in transformed mammalian cells. In this report, we show that E4orf4 induces an irreversible growth arrest in Saccharomyces cerevisiae at the G2/M phase of the cell cycle. Growth inhibition requires the presence of yeast PP2A-Cdc55, and is accompanied by accumulation of reactive oxygen species. E4orf4 expression is synthetically lethal with mutants defective in mitosis, including Cdc28/Cdk1 and anaphase-promoting complex/cyclosome (APC/C) mutants. Although APC/C activity is inhibited in the presence of E4orf4, Cdc28/Cdk1 is activated and partially counteracts the E4orf4-induced cell cycle arrest. The E4orf4–PP2A complex physically interacts with the APC/C, suggesting that E4orf4 functions by directly targeting PP2A to the APC/C, thereby leading to its inactivation. Finally, we show that E4orf4 can induce G2/M arrest in mammalian cells before apoptosis, indicating that E4orf4-induced events in yeast and mammalian cells are highly conserved.

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