Organelle morphogenesis by active membrane remodeling

Soft Matter ◽  
2015 ◽  
Vol 11 (12) ◽  
pp. 2387-2393 ◽  
Author(s):  
N. Ramakrishnan ◽  
John H. Ipsen ◽  
Madan Rao ◽  
P. B. Sunil Kumar

Eukaryotic cells are characterized by having well defined internal membrane bound organelles with distinct morphological identity. We explore the issue of morphogenesis in the context of organelles subject to intense membrane trafficking and show that non-equilibrium driven processes are at the heart of organelle morphogenesis.

2020 ◽  
Vol 22 (1) ◽  
pp. 1
Author(s):  
Alessandra Ferramosca

Mitochondria are double membrane-bound organelles which are essential for the viability of eukaryotic cells, because they play a crucial role in bioenergetics, metabolism and signaling [...]


Physiology ◽  
2010 ◽  
Vol 25 (6) ◽  
pp. 347-356 ◽  
Author(s):  
Fred D. Mast ◽  
Andrei Fagarasanu ◽  
Barbara Knoblach ◽  
Richard A. Rachubinski

Eukaryotic cells are characterized by their varied complement of organelles. One set of membrane-bound, usually spherical compartments are commonly grouped together under the term peroxisomes. Peroxisomes function in regulating the synthesis and availability of many diverse lipids by harnessing the power of oxidative reactions and contribute to a number of metabolic processes essential for cellular differentiation and organismal development.


1994 ◽  
Vol 298 (1) ◽  
pp. 143-148 ◽  
Author(s):  
J Hesketh ◽  
G Campbell ◽  
M Piechaczyk ◽  
J M Blanchard

The influence of the 3′ untranslated region on mRNA localization was investigated by measuring the distribution of myc, beta-globin and hybrid myc-globin mRNAs between free, cytoskeletal-bound and membrane-bound polysomes in cells transfected with either control or chimeric gene constructs. c-myc sequences and beta-globin-coding sequences linked to the myc 3′ untranslated region were present at greatest enrichment in cytoskeletal-bound polysomes. beta-Globin mRNA and myc-coding sequences linked to the beta-globin 3′ untranslated region were recovered largely in the free polysomes. In situ hybridization confirmed that replacement of the c-myc 3′ untranslated region by that of globin caused a relocalization of the mRNA. The results suggest that mRNA localization in differentiated eukaryotic cells depends on a mechanism that involves directional information in the 3′ untranslated region of mRNAs.


2014 ◽  
Vol 2014 ◽  
pp. 1-21 ◽  
Author(s):  
L. Shannon Holliday

Vacuolar H+-ATPases (V-ATPases) are large multisubunit proton pumps that are required for housekeeping acidification of membrane-bound compartments in eukaryotic cells. Mammalian V-ATPases are composed of 13 different subunits. Their housekeeping functions include acidifying endosomes, lysosomes, phagosomes, compartments for uncoupling receptors and ligands, autophagosomes, and elements of the Golgi apparatus. Specialized cells, including osteoclasts, intercalated cells in the kidney and pancreatic beta cells, contain both the housekeeping V-ATPases and an additional subset of V-ATPases, which plays a cell type specific role. The specialized V-ATPases are typically marked by the inclusion of cell type specific isoforms of one or more of the subunits. Three human diseases caused by mutations of isoforms of subunits have been identified. Cancer cells utilize V-ATPases in unusual ways; characterization of V-ATPases may lead to new therapeutic modalities for the treatment of cancer. Two accessory proteins to the V-ATPase have been identified that regulate the proton pump. One is the (pro)renin receptor and data is emerging that indicates that V-ATPase may be intimately linked to renin/angiotensin signaling both systemically and locally. In summary, V-ATPases play vital housekeeping roles in eukaryotic cells. Specialized versions of the pump are required by specific organ systems and are involved in diseases.


2003 ◽  
Vol 25 (3) ◽  
pp. 31-33
Author(s):  
John Lucocq

When I was a lad, the adage that “cells are not simply bags full of enzymes” was already popular in biology, and how true it turned out to be. We now know that eukaryotes comprise cellular compartments whose integrity and composition is maintained by specific mechanisms, including the membrane traffic between membrane-bound organelles. So what attracts cell biologists to the challenge of membrane traffic? One reason may be the complexity in composition and spatio-temporal dynamics -- a complexity that manifests itself in the sheer beauty of the physical forms of the trafficking organelles. Another motivation may be the simple question of how complex mixtures of substances can be moved around selectively in membrane-bound vesicles while maintaining the compositional integrity of organelles. Whatever the attraction, it is clear that the full molecular inventory of traffic machinery will be known soon, and we stand now on the threshold of a deeper understanding. It is therefore a good time to look at what has been achieved so far. Interestingly, the focus of membrane trafficking research has come full circle. Initially, discrete organelles with specialized functions were described and then came a mass of molecular information. Now, we are back to the organelles, trying to work out how they are built and how they function in a dynamic way. As in any story of science, the road to discovery has been crucially dependent on clever insights, married with technical developments at both molecular and atomic resolution.


2020 ◽  
Author(s):  
Moona Huttunen ◽  
Artur Yakimovich ◽  
Ian J. White ◽  
Janos Kriston-Vizi ◽  
Juan Martin-Serrano ◽  
...  

Unlike most enveloped viruses, poxvirus egress is a complex process whereby cytoplasmic single membrane-bound virions are wrapped in a cell-derived double membrane. These triple membrane-bound particles, termed intracellular enveloped virions (IEVs), are then released from infected cells by fusion. While the wrapping double membrane is thought to be derived from virus-modified trans-Golgi or early endosomal cisternae, the cellular factors that regulate virus wrapping remain largely undefined. To identify novel cell factors required for this process the prototypic poxvirus, vaccinia virus (VACV), was subjected to a high-throughput RNAi screen directed against cellular membrane trafficking proteins. Focusing on the endosomal sorting complexes required for transport (ESCRT), we demonstrate that ESCRT-III and VPS4 are required for packaging of virus into multivesicular bodies (MVBs). EM-based characterization of these MVB-IEVs showed that they account for half of IEV production indicating that MVBs serve as a second major source of VACV wrapping membrane. These data support a model whereby, in addition to cisternae-based wrapping, VACV hijacks ESCRT-mediated MVB formation to facilitate virus egress and spread.


2020 ◽  
Vol 12 (22) ◽  
pp. 2795-2811 ◽  
Author(s):  
Houman Kholafazad Kordasht ◽  
Mohammad Hasanzadeh

Exosomes are membrane-bound extracellular vesicles (EVs) that are produced in the endosomal compartments of most eukaryotic cells; they play important roles in intercellular communication in diverse cellular processes and transmit different types of biomolecules.


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