Distribution of Cell Membrane-associated Proteins Along the Human Nephron

ABSTRACT This study was undertaken to examine concomitant roles of pili and colony opacity-associated proteins (Opa) in promoting Neisseria gonorrhoeae adherence to and invasion of human endometrial HEC-1-B cells. Adherence of N. gonorrhoeae to cultured HEC-1-B cells was saturable, even though organisms adhered to <50% of the cells. During 4 to 6 h of incubation, adherent mono- and diplococci formed microcolonies on the surfaces of the cells. Microvilli of the HEC-1-B cells adhered by their distal ends to individual cocci within the microcolonies. When the microcolonies grew from isogenic pilus-negative (P−) Opa−, P− Opa+, or P+ Opa−gonococci, microvilli did not elongate, and the colonies were not engulfed. In contrast, the microvilli markedly elongated during exposure to P+ Opa+ gonococci. The microvilli adhered to the organisms along their full lengths and appeared to actively participate in the engulfment of the microcolonies. Internalized microcolonies, with P+ Opa+gonococci, contained dividing cocci and appeared to be surrounded by cell membrane but were not clearly within vacuoles. In contrast, degenerate individual organisms were within vacuoles. Low doses of chloramphenicol, which inhibits protein synthesis by both prokaryotes and eukaryotes, prevented the microvillar response to and internalization of the P+ Opa+ gonococci; higher doses caused internalization without microvillus activation. Cycloheximide and anisomycin, which inhibit only eukaryotic protein synthesis, caused dose-dependent enhancement of uptake. Cytochalasins reduced engulfment; colchicine had no effect. These results show that gonococci must express both pili and Opa to be engulfed efficiently by HEC-1-B cells.

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Flotillin-mediated endocytosis and ALIX–syntenin-1–mediated exocytosis protect the cell membrane from damage caused by necroptosis

Science Signaling ◽

10.1126/scisignal.aaw3423 ◽

2019 ◽

Vol 12 (583) ◽

pp. eaaw3423 ◽

Cited By ~ 18

Author(s):

Weiliang Fan ◽

Jia Guo ◽

Beichen Gao ◽

Wenbin Zhang ◽

Liucong Ling ◽

...

Keyword(s):

Plasma Membrane ◽

Cell Membrane ◽

Lipid Raft ◽

Affinity Purification ◽

Human Diseases ◽

Membrane Disruption ◽

Cross Linking ◽

Lysosomal Degradation ◽

Regulated Necrosis ◽

Associated Proteins

Necroptosis is a form of regulated necrosis that is implicated in various human diseases including Alzheimer’s disease. Necroptosis requires the translocation of the pseudokinase MLKL from the cytosol to the plasma membrane after its phosphorylation by the kinase RIPK3. Using protein cross-linking followed by affinity purification, we detected the lipid raft–associated proteins flotillin-1 and flotillin-2 and the ESCRT-associated proteins ALIX and syntenin-1 in membrane-localized MLKL immunoprecipitates. Phosphorylated MLKL was removed from membranes through either flotillin-mediated endocytosis followed by lysosomal degradation or ALIX–syntenin-1–mediated exocytosis. Thus, cells undergoing necroptosis need to overcome these independent suppressive mechanisms before plasma membrane disruption can occur.

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UNC-98 links an integrin-associated complex to thick filaments in Caenorhabditis elegans muscle

The Journal of Cell Biology ◽

10.1083/jcb.200608043 ◽

2006 ◽

Vol 175 (6) ◽

pp. 853-859 ◽

Cited By ~ 23

Author(s):

Rachel K. Miller ◽

Hiroshi Qadota ◽

Megan L. Landsverk ◽

Kristina B. Mercer ◽

Henry F. Epstein ◽

...

Keyword(s):

Caenorhabditis Elegans ◽

Cell Membrane ◽

Transmembrane Protein ◽

Focal Adhesions ◽

Terminal Portion ◽

Dense Bodies ◽

Thick Filaments ◽

Vertebrate Muscle ◽

Associated Proteins ◽

Lines Of Evidence

Focal adhesions are multiprotein assemblages that link cells to the extracellular matrix. The transmembrane protein, integrin, is a key component of these structures. In vertebrate muscle, focal adhesion–like structures called costameres attach myofibrils at the periphery of muscle cells to the cell membrane. In Caenorhabditis elegans muscle, all the myofibrils are attached to the cell membrane at both dense bodies (Z-disks) and M-lines. Clustered at the base of dense bodies and M-lines, and associated with the cytoplasmic tail of β-integrin, is a complex of many proteins, including UNC-97 (vertebrate PINCH). Previously, we showed that UNC-97 interacts with UNC-98, a 37-kD protein, containing four C2H2 Zn fingers, that localizes to M-lines. We report that UNC-98 also interacts with the C-terminal portion of a myosin heavy chain. Multiple lines of evidence support a model in which UNC-98 links integrin-associated proteins to myosin in thick filaments at M-lines.

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Anatomy of the red cell membrane skeleton: unanswered questions

Blood ◽

10.1182/blood-2014-12-512772 ◽

2016 ◽

Vol 127 (2) ◽

pp. 187-199 ◽

Cited By ~ 122

Author(s):

Samuel E. Lux

Keyword(s):

Cell Membrane ◽

Lipid Bilayer ◽

Membrane Surface ◽

Membrane Skeleton ◽

Actin Binding ◽

Red Cell ◽

Red Cell Membrane ◽

Associated Proteins ◽

Protein 4.1R ◽

Cell Skeleton

Abstract The red cell membrane skeleton is a pseudohexagonal meshwork of spectrin, actin, protein 4.1R, ankyrin, and actin-associated proteins that laminates the inner membrane surface and attaches to the overlying lipid bilayer via band 3–containing multiprotein complexes at the ankyrin- and actin-binding ends of spectrin. The membrane skeleton strengthens the lipid bilayer and endows the membrane with the durability and flexibility to survive in the circulation. In the 36 years since the first primitive model of the red cell skeleton was proposed, many additional proteins have been discovered, and their structures and interactions have been defined. However, almost nothing is known of the skeleton’s physiology, and myriad questions about its structure remain, including questions concerning the structure of spectrin in situ, the way spectrin and other proteins bind to actin, how the membrane is assembled, the dynamics of the skeleton when the membrane is deformed or perturbed by parasites, the role lipids play, and variations in membrane structure in unique regions like lipid rafts. This knowledge is important because the red cell membrane skeleton is the model for spectrin-based membrane skeletons in all cells, and because defects in the red cell membrane skeleton underlie multiple hemolytic anemias.

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BBSome: a New Player in Hypertension and Other Cardiovascular Risks

Hypertension ◽

10.1161/hypertensionaha.121.17946 ◽

2021 ◽

Author(s):

Yuying Zhao ◽

Kamal Rahmouni

Keyword(s):

Cell Membrane ◽

Vascular Reactivity ◽

Cardiovascular Health ◽

Cardiac Development ◽

Association Studies ◽

Renin Angiotensin System ◽

Cardiovascular Risks ◽

Cellular Processes ◽

Associated Proteins ◽

Obesity Hypertension

The BBSome is an octameric protein complex involved in Bardet-Biedl syndrome (BBS), a human pleiotropic, autosomal recessive condition. Patients with BBS display various clinical features including obesity, hypertension, and renal abnormalities. Association studies have also linked the BBS genes to hypertension and other cardiovascular risks in the general population. The BBSome was originally associated with the function of cilia, a highly specialized organelle that extend from the cell membrane of most vertebrate cells. However, subsequent studies have implicated the BBSome in the control of a myriad of other cellular processes not related to cilia including cell membrane localization of receptors and gene expression. The development of animal models of BBS such as mouse lines lacking various components of the BBSome and associated proteins has facilitated studying their role in the control of cardiovascular function and deciphering the pathophysiological mechanisms responsible for the cardiovascular aberrations associated with BBS. These studies revealed the importance of the neuronal, renal, vascular, and cardiac BBSome in the regulation of blood pressure, renal function, vascular reactivity, and cardiac development. The BBSome has also emerged as a critical regulator of key systems involved in cardiovascular control including the renin-angiotensin system. Better understanding of the influence of the BBSome on the molecular and physiological processes relevant to cardiovascular health and disease has the potential of identifying novel mechanisms underlying hypertension and other cardiovascular risks.

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Direct binding of sulfur mustard and chloroethyl ethyl sulphide to human cell membrane-associated proteins; implications for sulfur mustard pathology

Journal of Chromatography B ◽

10.1016/j.jchromb.2009.11.030 ◽

2010 ◽

Vol 878 (17-18) ◽

pp. 1426-1432 ◽

Cited By ~ 13

Author(s):

N.M. Sayer ◽

R. Whiting ◽

A.C. Green ◽

K. Anderson ◽

J. Jenner ◽

...

Keyword(s):

Cell Membrane ◽

Human Cell ◽

Sulfur Mustard ◽

Associated Proteins ◽

Direct Binding

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Inhibitors of bacterial tubulin target bacterial membranes in vivo

MedChemComm ◽

10.1039/c2md20127e ◽

2013 ◽

Vol 4 (1) ◽

pp. 112-119 ◽

Cited By ~ 32

Author(s):

Marie H. Foss ◽

Ye-Jin Eun ◽

Charles I. Grove ◽

Daniel A. Pauw ◽

Nohemy A. Sorto ◽

...

Keyword(s):

Cell Membrane ◽

Relative Magnitude ◽

Localization Pattern ◽

Bacterial Membranes ◽

E Coli ◽

Associated Proteins

The loss of ΔΨ disrupts the normal localization pattern of membrane-associated proteins. The cartoon and images depict the diffuse pattern of a polarly localized protein, MinD after reduction of ΔΨ in E. coli. The length of the line across the cell membrane depicts the relative magnitude of ΔΨ.

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Mycobacterium tuberculosis SigF Regulates Genes Encoding Cell Wall-Associated Proteins and Directly Regulates the Transcriptional Regulatory Gene phoY1

Journal of Bacteriology ◽

10.1128/jb.00201-07 ◽

2007 ◽

Vol 189 (11) ◽

pp. 4234-4242 ◽

Cited By ~ 47

Author(s):

Ernest P. Williams ◽

Jong-Hee Lee ◽

William R. Bishai ◽

Carlo Colantuoni ◽

Petros C. Karakousis

Keyword(s):

Cell Wall ◽

Mycobacterium Tuberculosis ◽

Cell Membrane ◽

Regulatory Gene ◽

Regulatory Protein ◽

Nutrient Starvation ◽

Membrane Properties ◽

Transcription Analysis ◽

Transcriptional Regulatory ◽

Associated Proteins

ABSTRACT Mycobacterium tuberculosis SigF is homologous to stress response and sporulation sigma factors in many bacteria. Consistent with a possible role in mycobacterial survival under stress conditions, M. tuberculosis sigF is strongly induced within cultured human macrophages and upon nutrient starvation, and SigF has been implicated in M. tuberculosis entry into stationary phase. On the other hand, SigF appears to contribute to the immune pathology of tuberculosis (TB), and a sigF-deficient mutant has altered cell membrane properties. Using an M. tuberculosis sigF deletion mutant, we show here that sigF is not required for bacillary survival under nutrient starvation conditions and within activated murine macrophages or for extracellular persistence in an in vivo granuloma model of latent TB infection. Using a chemically inducible recombinant strain to conditionally overexpress sigF, we did not observe arrest or retardation of growth in exponentially growing cultures or reduced susceptibility to rifampin and isoniazid. Consistent with our hypothesis that SigF may mediate TB immunopathogenesis by altering cell membrane properties, we found that overexpression of sigF resulted in the differential regulation of many cell wall-associated proteins, including members of the MmpL, PE, and PPE families, several of which have been shown to influence host-pathogen interactions. The most highly upregulated gene by quantitative reverse transcription-PCR at all time points following sigF induction was Rv3301c (phoY1), which encodes a probable transcriptional regulatory protein homologous to PhoU proteins involved in regulation of phosphate uptake. Using in vitro transcription analysis, we show that SigF directly regulates phoY1, whose proposed promoter sequence is GGATTG-N16-GGGTAT.

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Photoreceptor disk membrane substructures by means of the complementary freeze-fracture-replica methods

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100081644 ◽

1978 ◽

Vol 36 (2) ◽

pp. 156-157

Author(s):

A. Tonosaki ◽

M. Yamasaki ◽

H. Washioka ◽

J. Mizoguchi

Keyword(s):

Cell Membranes ◽

Freeze Fracture ◽

Purple Membrane ◽

Remarkable Case ◽

Single Face ◽

Disk Membrane ◽

Associated Proteins ◽

Photoreceptor Membranes

A vertebrate disk membrane is composed of 40 % lipids and 60 % proteins. Its fracture faces have been classed into the plasmic (PF) and exoplasmic faces (EF), complementary with each other, like those of most other types of cell membranes. The hypothesis assuming the PF particles as representing membrane-associated proteins has been challenged by serious questions if they in fact emerge from the crystalline formation or decoration effects during freezing and shadowing processes. This problem seems to be yet unanswered, despite the remarkable case of the purple membrane of Halobacterium, partly because most observations have been made on the replicas from a single face of specimen, and partly because, in the case of photoreceptor membranes, the conformation of a rhodopsin and its relatives remains yet uncertain. The former defect seems to be partially fulfilled with complementary replica methods.

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