scholarly journals The Cirque du Soleil of Golgi membrane dynamics

2009 ◽  
Vol 186 (2) ◽  
pp. 169-171 ◽  
Author(s):  
Vytas A. Bankaitis
Keyword(s):  
Lysophosphatidic Acid ◽  
Metabolic Enzymes ◽  
Membrane Dynamics ◽  
Membrane Remodeling ◽  
Golgi Membrane ◽  
Tubule Formation ◽  
Cirque Du Soleil ◽  
Cell Biol

The role of lipid metabolic enzymes in Golgi membrane remodeling is a subject of intense interest. Now, in this issue, Schmidt and Brown (2009. J. Cell Biol. doi:10.1083/jcb.200904147) report that lysophosphatidic acid–specific acyltransferase, LPAAT3, contributes to Golgi membrane dynamics by suppressing tubule formation.

The Role of BAR Domain Proteins in the Regulation of Membrane Dynamics

Acta Naturae ◽  
2016 ◽  
Vol 8 (4) ◽  
pp. 60-69 ◽  
Author(s):  
T. B. Stanishneva-Konovalova ◽  
N. I Derkacheva ◽  
S. V. Polevova ◽  
O. S. Sokolova
Keyword(s):  
Membrane Dynamics ◽  
Actin Dynamics ◽  
Membrane Remodeling ◽  
Bar Domain ◽  
Cellular Processes ◽  
Functional Differences ◽  
Bar Domain Proteins ◽  
Domain Protein ◽  
Bar Domains

Many cellular processes are associated with membrane remodeling. The BAR domain protein family plays a key role in the formation and detection of local membrane curvatures and in attracting other proteins, including the regulators of actin dynamics. Based on their structural and phylogenetic properties, BAR domains are divided into several groups which affect membrane in various ways and perform different functions in cells. However, recent studies have uncovered evidence of functional differences even within the same group. This review discusses the principles underlying the interactions of different groups of BAR domains, and their individual representatives, with membranes.

scholarly journals Lysophosphatidic acid acyltransferase 3 regulates Golgi complex structure and function

2009 ◽  
Vol 186 (2) ◽  
pp. 211-218 ◽  
Author(s):  
John A. Schmidt ◽  
William J. Brown
Keyword(s):  
Lysophosphatidic Acid ◽  
Golgi Complex ◽  
Membrane Trafficking ◽  
Functional Organization ◽  
Complex Structure ◽  
Golgi Membrane ◽  
Direct Role ◽  
Tubule Formation ◽  
In Cells

Recent studies have suggested that the functional organization of the Golgi complex is dependent on phospholipid remodeling enzymes. Here, we report the identification of an integral membrane lysophosphatidic acid–specific acyltransferase, LPAAT3, which regulates Golgi membrane tubule formation, trafficking, and structure by altering phospholipids and lysophospholipids. Overexpression of LPAAT3 significantly inhibited the formation of Golgi membrane tubules in vivo and in vitro. Anterograde and retrograde protein trafficking was slower in cells overexpressing LPAAT3 and accelerated in cells with reduced expression (by siRNA). Golgi morphology was also dependent on LPAAT3 because its knockdown caused the Golgi to become fragmented. These data are the first to show a direct role for a specific phospholipid acyltransferase in regulating membrane trafficking and organelle structure.

scholarly journals The role of VPS4 in ESCRT-III polymer remodeling

2019 ◽  
Vol 47 (1) ◽  
pp. 441-448 ◽  
Author(s):  
Christophe Caillat ◽  
Sourav Maity ◽  
Nolwenn Miguet ◽  
Wouter H. Roos ◽  
Winfried Weissenhorn
Keyword(s):  
Active Role ◽  
Mechanistic Models ◽  
Membrane Remodeling ◽  
Filament Formation ◽  
Enveloped Viruses ◽  
Endosomal Sorting ◽  
Membrane Fission ◽  
Dynamic Assembly ◽  
Inside Out

Abstract The endosomal sorting complex required for transport-III (ESCRT-III) and VPS4 catalyze a variety of membrane-remodeling processes in eukaryotes and archaea. Common to these processes is the dynamic recruitment of ESCRT-III proteins from the cytosol to the inner face of a membrane neck structure, their activation and filament formation inside or at the membrane neck and the subsequent or concomitant recruitment of the AAA-type ATPase VPS4. The dynamic assembly of ESCRT-III filaments and VPS4 on cellular membranes induces constriction of membrane necks with large diameters such as the cytokinetic midbody and necks with small diameters such as those of intraluminal vesicles or enveloped viruses. The two processes seem to use different sets of ESCRT-III filaments. Constriction is then thought to set the stage for membrane fission. Here, we review recent progress in understanding the structural transitions of ESCRT-III proteins required for filament formation, the functional role of VPS4 in dynamic ESCRT-III assembly and its active role in filament constriction. The recent data will be discussed in the context of different mechanistic models for inside-out membrane fission.

scholarly journals The activity status of cofilin is directly related to invasion, intravasation, and metastasis of mammary tumors

2006 ◽  
Vol 173 (3) ◽  
pp. 395-404 ◽  
Author(s):  
Weigang Wang ◽  
Ghassan Mouneimne ◽  
Mazen Sidani ◽  
Jeffrey Wyckoff ◽  
Xiaoming Chen ◽  
...  
Keyword(s):  
Cell Motility ◽  
Cell Invasion ◽  
Actin Polymerization ◽  
Cancer Cell Invasion ◽  
Invasion And Metastasis ◽  
Over Expression ◽  
Cell Biol ◽  
Tumor Cell Motility ◽  
New Strategies

Understanding the mechanisms controlling cancer cell invasion and metastasis constitutes a fundamental step in setting new strategies for diagnosis, prognosis, and therapy of metastatic cancers. LIM kinase1 (LIMK1) is a member of a novel class of serine–threonine protein kinases. Cofilin, a LIMK1 substrate, is essential for the regulation of actin polymerization and depolymerization during cell migration. Previous studies have made opposite conclusions as to the role of LIMK1 in tumor cell motility and metastasis, claiming either an increase or decrease in cell motility and metastasis as a result of LIMK1 over expression (Zebda, N., O. Bernard, M. Bailly, S. Welti, D.S. Lawrence, and J.S. Condeelis. 2000. J. Cell Biol. 151:1119–1128; Davila, M., A.R. Frost, W.E. Grizzle, and R. Chakrabarti. 2003. J. Biol. Chem. 278:36868–36875; Yoshioka, K., V. Foletta, O. Bernard, and K. Itoh. 2003. Proc. Natl. Acad. Sci. USA. 100:7247–7252; Nishita, M., C. Tomizawa, M. Yamamoto, Y. Horita, K. Ohashi, and K. Mizuno. 2005. J. Cell Biol. 171:349–359). We resolve this paradox by showing that the effects of LIMK1 expression on migration, intravasation, and metastasis of cancer cells can be most simply explained by its regulation of the output of the cofilin pathway. LIMK1-mediated decreases or increases in the activity of the cofilin pathway are shown to cause proportional decreases or increases in motility, intravasation, and metastasis of tumor cells.

scholarly journals A Novel Golgi Membrane Protein Is a Partner of the ARF Exchange Factors Gea1p and Gea2p

2003 ◽  
Vol 14 (6) ◽  
pp. 2357-2371 ◽  
Author(s):  
Sophie Chantalat ◽  
Rëgis Courbeyrette ◽  
Francesca Senic-Matuglia ◽  
Catherine L. Jackson ◽  
Bruno Goud ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Protein Trafficking ◽  
Transmembrane Domain ◽  
Integral Membrane Protein ◽  
Membrane Dynamics ◽  
General Interest ◽  
Single Mutation ◽  
Golgi Membrane ◽  
Nucleotide Exchange

The Sec7 domain guanine nucleotide exchange factors (GEFs) for the GTPase ARF are highly conserved regulators of membrane dynamics and protein trafficking. The interactions of large ARF GEFs with cellular membranes for localization and/or activation are likely to participate in regulated recruitment of ARF and effectors. However, these interactions remain largely unknown. Here we characterize Gmh1p, the first Golgi transmembrane-domain partner of any of the high-molecular-weight ARF-GEFs. Gmh1p is an evolutionarily conserved protein. We demonstrate molecular interaction between the yeast Gmh1p and the large ARF-GEFs Gea1p and Gea2p. This interaction involves a domain of Gea1p and Gea2p that is conserved in the eukaryotic orthologues of the Gea proteins. A single mutation in a conserved amino acid residue of this domain is sufficient to abrogate the interaction, whereas the overexpression of Gmh1p can compensate in vivo defects caused by mutations in this domain. We show that Gmh1p is an integral membrane protein that localizes to the early Golgi in yeast and in human HeLa cells and cycles through the ER. Hence, we propose that Gmh1p acts as a positive Golgi-membrane partner for Gea function. These results are of general interest given the evolutionary conservation of both ARF-GEFs and the Gmh proteins.

scholarly journals Cells in tight spaces: the role of cell shape in cell function

2010 ◽  
Vol 191 (2) ◽  
pp. 233-236 ◽  
Author(s):  
Jagesh V. Shah
Keyword(s):  
Primary Cilium ◽  
Cell Shape ◽  
Cell Function ◽  
Cellular Function ◽  
Cell Geometry ◽  
Intracellular Organization ◽  
Cell Biol

In this issue, Pitaval et al. (2010. J. Cell Biol. doi:10.1083/jcb.201004003) demonstrate that cell geometry can regulate the elaboration of a primary cilium. Their findings and approaches are part of a historical line of inquiry investigating the role of cell shape in intracellular organization and cellular function.

scholarly journals Expression of lysophosphatidic acid receptor 5 is necessary for the regulation of intestinal Na+/H+ exchanger 3 by lysophosphatidic acid in vivo

2018 ◽  
Vol 315 (4) ◽  
pp. G433-G442 ◽  
Author(s):  
Kayte A. Jenkin ◽  
Peijian He ◽  
C. Chris Yun
Keyword(s):  
Epithelial Cells ◽  
Lysophosphatidic Acid ◽  
Direct Evidence ◽  
Intestinal Epithelial Cells ◽  
Regulatory Role ◽  
Intestinal Epithelial ◽  
Fluid Absorption ◽  
Wild Type

Lysophosphatidic acid (LPA) is a bioactive lipid molecule, which regulates a broad range of pathophysiological processes. Recent studies have demonstrated that LPA modulates electrolyte flux in the intestine, and its potential as an antidiarrheal agent has been suggested. Of six LPA receptors, LPA5 is highly expressed in the intestine. Recent studies by our group have demonstrated activation of Na+/H+ exchanger 3 (NHE3) by LPA5. However, much of what has been elucidated was achieved using colonic cell lines that were transfected to express LPA5. In the current study, we engineered a mouse that lacks LPA5 in intestinal epithelial cells, Lpar5ΔIEC, and investigated the role of LPA5 in NHE3 regulation and fluid absorption in vivo. The intestine of Lpar5ΔIEC mice appeared morphologically normal, and the stool frequency and fecal water content were unchanged compared with wild-type mice. Basal rates of NHE3 activity and fluid absorption and total NHE3 expression were not changed in Lpar5ΔIEC mice. However, LPA did not activate NHE3 activity or fluid absorption in Lpar5ΔIEC mice, providing direct evidence for the regulatory role of LPA5. NHE3 activation involves trafficking of NHE3 from the terminal web to microvilli, and this mobilization of NHE3 by LPA was abolished in Lpar5ΔIEC mice. Dysregulation of NHE3 was specific to LPA, and insulin and cholera toxin were able to stimulate and inhibit NHE3, respectively, in both wild-type and Lpar5ΔIEC mice. The current study for the first time demonstrates the necessity of LPA5 in LPA-mediated stimulation of NHE3 in vivo. NEW & NOTEWORTHY This study is the first to assess the role of LPA5 in NHE3 regulation and fluid absorption in vivo using a mouse that lacks LPA5 in intestinal epithelial cells, Lpar5ΔIEC. Basal rates of NHE3 activity and fluid absorption, and total NHE3 expression were not changed in Lpar5ΔIEC mice. However, LPA did not activate NHE3 activity or fluid absorption in Lpar5ΔIEC mice, providing direct evidence for the regulatory role of LPA5.

scholarly journals The first “Slit” is the deepest: the secret to a hollow heart

2008 ◽  
Vol 182 (2) ◽  
pp. 221-223 ◽  
Author(s):  
Iiro Taneli Helenius ◽  
Greg J. Beitel
Keyword(s):  
Cell Shape ◽  
Vascular System ◽  
Hollow Heart ◽  
Autocrine Signaling ◽  
Lumen Formation ◽  
Membrane Surfaces ◽  
Vascular Morphogenesis ◽  
Cell Biol ◽  
Shape Changes

Tubular organs are essential for life, but lumen formation in nonepithelial tissues such as the vascular system or heart is poorly understood. Two studies in this issue (Medioni, C., M. Astier, M. Zmojdzian, K. Jagla, and M. Sémériva. 2008. J. Cell Biol. 182:249–261; Santiago-Martínez, E., N.H. Soplop, R. Patel, and S.G. Kramer. 2008. J. Cell Biol. 182:241–248) reveal unexpected roles for the Slit–Robo signaling system during Drosophila melanogaster heart morphogenesis. In cardioblasts, Slit and Robo modulate the cell shape changes and domains of E-cadherin–based adhesion that drive lumen formation. Furthermore, in contrast to the well-known paracrine role of Slit and Robo in guiding cell migrations, here Slit and Robo may act by autocrine signaling. In addition, the two groups demonstrate that heart lumen formation is even more distinct from typical epithelial tubulogenesis mechanisms because the heart lumen is bounded by membrane surfaces that have basal rather than apical attributes. As the D. melanogaster cardioblasts are thought to have significant evolutionary similarity to vertebrate endothelial and cardiac lineages, these findings are likely to provide insights into mechanisms of vertebrate heart and vascular morphogenesis.

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