Distinct cellular functions mediated by haemopoietic cell-surface proteases

The carbon-replica technique can be used to obtain information about cell-surface structure that cannot ordinarily be obtained by thin-section techniques. Mammalian erythrocytes have been studied by the replica technique and they appear to be characterized by a pebbly or “plaqued“ surface texture. The characteristic “particle” diameter is about 200 Å to 400 Å. We have now extended our observations on cell-surface structure to chicken and frog erythrocytes, which possess a broad range of cellular functions, and to normal rat lymphocytes and mouse ascites tumor cells, which are capable of cell division. In these experiments fresh cells were washed in Eagle's Minimum Essential Medium Salt Solution (for suspension cultures) and one volume of a 10% cell suspension was added to one volume of 2% OsO4 or 5% gluteraldehyde in 0.067 M phosphate buffer, pH 7.3. Carbon replicas were obtained by a technique similar to that employed by Glaeser et al. Figure 1 shows an electron micrograph of a carbon replica made from a chicken erythrocyte, and Figure 2 shows an enlarged portion of the same cell.

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Visualizing the dynamics of exported bacterial proteins with the chemogenetic fluorescent reporter FAST

10.1101/2020.05.12.090142 ◽

2020 ◽

Cited By ~ 1

Author(s):

Yankel Chekli ◽

Caroline Peron-Cane ◽

Dario Dell’Arciprete ◽

Jean-François Allemand ◽

Chenge Li ◽

...

Keyword(s):

Escherichia Coli ◽

Listeria Monocytogenes ◽

Cell Surface ◽

Bacterial Cell ◽

Surface Proteins ◽

Cellular Functions ◽

Reporter Protein ◽

Cell Surface Proteins ◽

Fluorescent Reporter ◽

Bacterial Proteins

AbstractBacterial proteins exported to the cell surface play key cellular functions. However, despite the interest to study the localization of surface proteins such as adhesins, transporters or hydrolases, monitoring their dynamics in live imaging remains challenging, due to the limited availability of fluorescent probes remaining functional after secretion. In this work, we used the Escherichia coli intimin and the Listeria monocytogenes InlB invasin as surface exposed scaffolds fused with the recently developed chemogenetic fluorescent reporter protein FAST. Using both membrane permeant (HBR-3,5DM) and non-permeant (HBRAA-3E) fluorogens that fluoresce upon binding to FAST, we demonstrated that fully functional FAST can be exposed at the cell surface and specifically tagged on the external side of the bacterial envelop in both diderm and monoderm bacteria. Our work opens new avenues to study of the organization and dynamics of the bacterial cell surface proteins.

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Integrin-Targeting Peptides for the Design of Functional Cell-Responsive Biomaterials

Biomedicines ◽

10.3390/biomedicines8090307 ◽

2020 ◽

Vol 8 (9) ◽

pp. 307 ◽

Cited By ~ 1

Author(s):

Junwei Zhao ◽

Federica Santino ◽

Daria Giacomini ◽

Luca Gentilucci

Keyword(s):

Cell Surface ◽

Smart Materials ◽

Drug Carrier ◽

Peptide Ligands ◽

Stimuli Responsive ◽

Cellular Functions ◽

Surface Receptors ◽

Integrin Ligands ◽

Carrier Systems ◽

Drug Carrier Systems

Integrins are a family of cell surface receptors crucial to fundamental cellular functions such as adhesion, signaling, and viability, deeply involved in a variety of diseases, including the initiation and progression of cancer, of coronary, inflammatory, or autoimmune diseases. The natural ligands of integrins are glycoproteins expressed on the cell surface or proteins of the extracellular matrix. For this reason, short peptides or peptidomimetic sequences that reproduce the integrin-binding motives have attracted much attention as potential drugs. When challenged in clinical trials, these peptides/peptidomimetics let to contrasting and disappointing results. In the search for alternative utilizations, the integrin peptide ligands have been conjugated onto nanoparticles, materials, or drugs and drug carrier systems, for specific recognition or delivery of drugs to cells overexpressing the targeted integrins. Recent research in peptidic integrin ligands is exploring new opportunities, in particular for the design of nanostructured, micro-fabricated, cell-responsive, stimuli-responsive, smart materials.

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The Spectrinome: The Interactome of a Scaffold Protein Creating Nuclear and Cytoplasmic Connectivity and Function

Experimental Biology and Medicine ◽

10.1177/1535370219867269 ◽

2019 ◽

Vol 244 (15) ◽

pp. 1273-1302 ◽

Cited By ~ 3

Author(s):

Steven R. Goodman ◽

Daniel Johnson ◽

Steven L. Youngentob ◽

David Kakhniashvili

Keyword(s):

Cell Surface ◽

Intracellular Signaling ◽

Cellular Protein ◽

Human Diseases ◽

Scaffolding Protein ◽

Eukaryotic Cells ◽

Cellular Functions ◽

Cellular Compartment ◽

Atlas Data ◽

And Function

We provide a review of Spectrin isoform function in the cytoplasm, the nucleus, the cell surface, and in intracellular signaling. We then discuss the importance of Spectrin’s E2/E3 chimeric ubiquitin conjugating and ligating activity in maintaining cellular homeostasis. Finally we present spectrin isoform subunit specific human diseases. We have created the Spectrinome, from the Human Proteome, Human Reactome and Human Atlas data and demonstrated how it can be a useful tool in visualizing and understanding spectrins myriad of cellular functions. Impact statement Spectrin was for the first 12 years after its discovery thought to be found only in erythrocytes. In 1981, Goodman and colleagues 1 found that spectrin-like molecules were ubiquitously found in non-erythroid cells leading to a great multitude of publications over the next thirty eight years. The discovery of multiple spectrin isoforms found associated with every cellular compartment, and representing 2-3% of cellular protein, has brought us to today’s understanding that spectrin is a scaffolding protein, with its own E2/E3 chimeric ubiquitin conjugating ligating activity that is involved in virtually every cellular function. We cover the history, localized functions of spectrin isoforms, human diseases caused by mutations, and provide the spectrinome: a useful tool for understanding the myriad of functions for one of the most important proteins in all eukaryotic cells.

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Targeting heparin and heparan sulfate protein interactions

Organic & Biomolecular Chemistry ◽

10.1039/c7ob01058c ◽

2017 ◽

Vol 15 (27) ◽

pp. 5656-5668 ◽

Cited By ~ 44

Author(s):

Ryan J. Weiss ◽

Jeffrey D. Esko ◽

Yitzhak Tor

Keyword(s):

Extracellular Matrix ◽

Cell Surface ◽

Heparan Sulfate ◽

Protein Interactions ◽

Human Disease ◽

Binding Proteins ◽

Cellular Functions ◽

Animal Cells ◽

Carbohydrate Chains

Heparan sulfate is ubiquitously expressed on the cell surface and in the extracellular matrix of all animal cells. These negatively-charged carbohydrate chains play essential roles in many important cellular functions by interacting with various heparan sulfate binding proteins (HSBP). This review discusses methods for targeting these complex biomolecules, as strategies for treating human disease.

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Syndecans: multifunctional cell-surface co-receptors

Biochemical Journal ◽

10.1042/bj3270001 ◽

1997 ◽

Vol 327 (1) ◽

pp. 1-16 ◽

Cited By ~ 467

Author(s):

David J. CAREY

Keyword(s):

Cell Surface ◽

Heparan Sulphate ◽

Biochemical Properties ◽

Main Function ◽

Cellular Functions ◽

Structural Domains ◽

Cell Matrix ◽

Current State ◽

Core Proteins ◽

Membrane Compartment

This review will summarize our current state of knowledge of the structure, biochemical properties and functions of syndecans, a family of transmembrane heparan sulphate proteoglycans. Syndecans bind a variety of extracellular ligands via their covalently attached heparan sulphate chains. Syndecans have been proposed to play a role in a variety of cellular functions, including cell proliferation and cell–matrix and cell–cell adhesion. Syndecan expression is highly regulated and is cell-type- and developmental-stage-specific. The main function of syndecans appears to be to modulate the ligand-dependent activation of primary signalling receptors at the cell surface. Principal functions of the syndecan core proteins are to target the heparan sulphate chains to the appropriate plasma-membrane compartment and to interact with components of the actin-based cytoskeleton. Several functions of the syndecans, including syndecan oligomerization and actin cytoskeleton association, have been localized to specific structural domains of syndecan core proteins.

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A mammalian homolog of the zebrafish transmembrane protein 2 (TMEM2) is the long-sought-after cell-surface hyaluronidase

Journal of Biological Chemistry ◽

10.1074/jbc.m116.770149 ◽

2017 ◽

Vol 292 (18) ◽

pp. 7304-7313 ◽

Cited By ~ 56

Author(s):

Hayato Yamamoto ◽

Yuki Tobisawa ◽

Toshihiro Inubushi ◽

Fumitoshi Irie ◽

Chikara Ohyama ◽

...

Keyword(s):

Cell Surface ◽

Dermatan Sulfate ◽

Transmembrane Protein ◽

Live Cells ◽

Dependent Manner ◽

Cellular Functions ◽

Ph Optimum ◽

Hyaluronidase Activity ◽

A Cell ◽

Intermediate Size

Hyaluronan (HA) is an extremely large polysaccharide (glycosaminoglycan) involved in many cellular functions. HA catabolism is thought to involve the initial cleavage of extracellular high-molecular-weight (HMW) HA into intermediate-size HA by an extracellular or cell-surface hyaluronidase, internalization of intermediate-size HA, and complete degradation into monosaccharides in lysosomes. Despite considerable research, the identity of the hyaluronidase responsible for the initial HA cleavage in the extracellular space remains elusive. HYAL1 and HYAL2 have properties more consistent with lysosomal hyaluronidases, whereas CEMIP/KIAA1199, a recently identified HA-binding molecule that has HA-degrading activity, requires the participation of the clathrin-coated pit pathway of live cells for HA degradation. Here we show that transmembrane protein 2 (TMEM2), a mammalian homolog of a protein playing a role in zebrafish endocardial cushion development, is a cell-surface hyaluronidase. Live immunostaining and surface biotinylation assays confirmed that mouse TMEM2 is expressed on the cell surface in a type II transmembrane topology. TMEM2 degraded HMW-HA into ∼5-kDa fragments but did not cleave chondroitin sulfate or dermatan sulfate, indicating its specificity to HA. The hyaluronidase activity of TMEM2 was Ca2+-dependent; the enzyme's pH optimum is around 6–7, and unlike CEMIP/KIAA1199, TMEM2 does not require the participation of live cells for its hyaluronidase activity. Moreover, TMEM2-expressing cells could eliminate HA immobilized on a glass surface in a contact-dependent manner. Together, these data suggest that TMEM2 is the long-sought-after hyaluronidase that cleaves extracellular HMW-HA into intermediate-size fragments before internalization and degradation in the lysosome.

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Molecular mechanism of Fast Endophilin-Mediated Endocytosis

Biochemical Journal ◽

10.1042/bcj20190342 ◽

2020 ◽

Vol 477 (12) ◽

pp. 2327-2345 ◽

Cited By ~ 3

Author(s):

Alessandra Casamento ◽

Emmanuel Boucrot

Keyword(s):

Plasma Membrane ◽

Cell Surface ◽

Molecular Mechanism ◽

Receptor Activation ◽

Membrane Curvature ◽

Surface Proteins ◽

Resting Cells ◽

Cellular Functions ◽

Surface Receptors ◽

Key Steps

Endocytosis mediates the cellular uptake of micronutrients and cell surface proteins. Clathrin-mediated endocytosis (CME) is the housekeeping pathway in resting cells but additional Clathrin-independent endocytic (CIE) routes, including Fast Endophilin-Mediated Endocytosis (FEME), internalize specific cargoes and support diverse cellular functions. FEME is part of the Dynamin-dependent subgroup of CIE pathways. Here, we review our current understanding of the molecular mechanism of FEME. Key steps are: (i) priming, (ii) cargo selection, (iii) membrane curvature and carrier formation, (iv) membrane scission and (v) cytosolic transport. All steps are controlled by regulatory mechanisms mediated by phosphoinositides and by kinases such as Src, LRRK2, Cdk5 and GSK3β. A key feature of FEME is that it is not constitutively active but triggered upon the stimulation of selected cell surface receptors by their ligands. In resting cells, there is a priming cycle that concentrates Endophilin into clusters on discrete locations of the plasma membrane. In the absence of receptor activation, the patches quickly abort and new cycles are initiated nearby, constantly priming the plasma membrane for FEME. Upon activation, receptors are swiftly sorted into pre-existing Endophilin clusters, which then bud to form FEME carriers within 10 s. We summarize the hallmarks of FEME and the techniques and assays required to identify it. Next, we review similarities and differences with other CIE pathways and proposed cargoes that may use FEME to enter cells. Finally, we submit pending questions and future milestones and discuss the exciting perspectives that targeting FEME may boost treatments against cancer and neurodegenerative diseases.

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Nucleic acid-based molecular computation heads towards cellular applications

Chemical Society Reviews ◽

10.1039/d0cs01508c ◽

2021 ◽

Author(s):

Lanlan Chen ◽

Wanzhen Chen ◽

Guo Liu ◽

Jingying Li ◽

Chunhua Lu ◽

...

Keyword(s):

Nucleic Acid ◽

Cell Surface ◽

Surface Proteins ◽

Specific Interactions ◽

Cellular Functions ◽

Cell Surface Proteins ◽

Molecular Computation ◽

Cellular Behaviors

Nucleic acid-based molecular computation for cellular applications, including specific interactions with cell surface proteins, biosensing, mimicking cellular behaviors, and engineering cellular functions.

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