scholarly journals Integrin α6β4 recognition of a linear motif of bullous pemphigoid antigen BP230 controls its recruitment to hemidesmosomes

2018 ◽  
Author(s):  
José A Manso ◽  
Maria Gómez-Hernández ◽  
Arturo Carabias ◽  
Noelia Alonso-García ◽  
Inés García-Rubio ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Basement Membrane ◽  
Molecular Mechanisms ◽  
Mechanical Stability ◽  
Human Keratinocytes ◽  
Linear Motif ◽  
The Third ◽  
Linear Sequence ◽  
Integrin Α6β4

AbstractMechanical stability of epithelia requires firm attachment to the basement membrane via hemidesmosomes. Dysfunction of hemidesmosomal proteins causes severe skin blistering diseases. Two plakins, plectin and BP230 (BPAG1e), link the integrin α6β4 to intermediate filaments in epidermal hemidesmosomes. Here, we show that a linear sequence within the isoform-specific N-terminal region of BP230 binds to the third and fourth FnIII domains of β4. The crystal structure of the complex and mutagenesis analysis revealed that BP230 binds between the two domains of β4. BP230 induces closing of the two FnIII domains that are looked in place by an inter-domain ionic clasp required for binding. Disruption of the BP230-β4 interface prevents the recruitment of BP230 to hemidesmosomes in human keratinocytes, revealing a key role of the BP230-β4 interaction for hemidesmosome assembly. Phosphomimetic substitutions in β4 and BP230 disrupt binding. Our study provides insights into the molecular mechanisms of hemidesmosome architecture and regulation.

Regulation of hemidesmosome dynamics and cell signaling by integrin α6β4

2021 ◽  
Vol 134 (18) ◽  
Author(s):  
Lisa te Molder ◽  
Jose M. de Pereda ◽  
Arnoud Sonnenberg
Keyword(s):  
Signal Transduction ◽  
Extracellular Matrix ◽  
Cell Adhesion ◽  
Epithelial Cells ◽  
Basement Membrane ◽  
Molecular Mechanisms ◽  
Vital Role ◽  
Cellular Processes ◽  
Integrin Α6β4

ABSTRACT Hemidesmosomes (HDs) are specialized multiprotein complexes that connect the keratin cytoskeleton of epithelial cells to the extracellular matrix (ECM). In the skin, these complexes provide stable adhesion of basal keratinocytes to the underlying basement membrane. Integrin α6β4 is a receptor for laminins and plays a vital role in mediating cell adhesion by initiating the assembly of HDs. In addition, α6β4 has been implicated in signal transduction events that regulate diverse cellular processes, including proliferation and survival. In this Review, we detail the role of α6β4 in HD assembly and beyond, and we discuss the molecular mechanisms that regulate its function.

scholarly journals Role and Molecular Mechanisms of Pericytes in Regulation of Leukocyte Diapedesis in Inflamed Tissues

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Paulina Rudziak ◽  
Christopher G. Ellis ◽  
Paulina M. Kowalewska
Keyword(s):  
Basement Membrane ◽  
Matrix Protein ◽  
Molecular Mechanisms ◽  
Leukocyte Recruitment ◽  
Extracellular Matrix Protein ◽  
Chemotactic Migration ◽  
Blood Vessel Formation ◽  
Vascular Basement Membrane ◽  
Leukocyte Extravasation

Leukocyte recruitment is a hallmark of the inflammatory response. Migrating leukocytes breach the endothelium along with the vascular basement membrane and associated pericytes. While much is known about leukocyte-endothelial cell interactions, the mechanisms and role of pericytes in extravasation are poorly understood and the classical paradigm of leukocyte recruitment in the microvasculature seldom adequately discusses the involvement of pericytes. Emerging evidence shows that pericytes are essential players in the regulation of leukocyte extravasation in addition to their functions in blood vessel formation and blood-brain barrier maintenance. Junctions between venular endothelial cells are closely aligned with extracellular matrix protein low expression regions (LERs) in the basement membrane, which in turn are aligned with gaps between pericytes. This forms preferential paths for leukocyte extravasation. Breaching of the layer formed by pericytes and the basement membrane entails remodelling of LERs, leukocyte-pericyte adhesion, crawling of leukocytes on pericyte processes, and enlargement of gaps between pericytes to form channels for migrating leukocytes. Furthermore, inflamed arteriolar and capillary pericytes induce chemotactic migration of leukocytes that exit postcapillary venules, and through direct pericyte-leukocyte contact, they induce efficient interstitial migration to enhance the immunosurveillance capacity of leukocytes. Given their role as regulators of leukocyte extravasation, proper pericyte function is imperative in inflammatory disease contexts such as diabetic retinopathy and sepsis. This review summarizes research on the molecular mechanisms by which pericytes mediate leukocyte diapedesis in inflamed tissues.

scholarly journals To form and function: on the role of basement membrane mechanics in tissue development, homeostasis and disease

Open Biology ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 200360
Author(s):  
Nargess Khalilgharibi ◽  
Yanlan Mao
Keyword(s):  
Basement Membrane ◽  
Molecular Mechanisms ◽  
Disease Diagnosis ◽  
Membrane Mechanics ◽  
Form And Function ◽  
And Function ◽  
Tissue Form

The basement membrane (BM) is a special type of extracellular matrix that lines the basal side of epithelial and endothelial tissues. Functionally, the BM is important for providing physical and biochemical cues to the overlying cells, sculpting the tissue into its correct size and shape. In this review, we focus on recent studies that have unveiled the complex mechanical properties of the BM. We discuss how these properties can change during development, homeostasis and disease via different molecular mechanisms, and the subsequent impact on tissue form and function in a variety of organisms. We also explore how better characterization of BM mechanics can contribute to disease diagnosis and treatment, as well as development of better in silico and in vitro models that not only impact the fields of tissue engineering and regenerative medicine, but can also reduce the use of animals in research.

scholarly journals Staphylococcus epidermidis Activates Aryl Hydrocarbon Receptor Signaling in Human Keratinocytes: Implications for Cutaneous Defense

2018 ◽  
Vol 11 (2) ◽  
pp. 125-135 ◽  
Author(s):  
Franziska Rademacher ◽  
Maren Simanski ◽  
Bettina Hesse ◽  
Gregor Dombrowsky ◽  
Nikolas Vent ◽  
...  
Keyword(s):  
Aryl Hydrocarbon Receptor ◽  
Staphylococcus Epidermidis ◽  
Molecular Mechanisms ◽  
Human Keratinocytes ◽  
Skin Equivalent ◽  
Dependent Manner ◽  
Cytochrome P450 1A1 ◽  
Aryl Hydrocarbon ◽  
Skin Explants

Bacterial challenge of keratinocytes with the abundant skin commensal Staphylococcus epidermidis induces distinct innate immune responses, but the underlying molecular mechanisms are still emerging. We report that the aryl hydrocarbon receptor (AhR) was activated in human primary keratinocytes infected with S. epidermidis, leading to induction of the AhR-responsive gene cytochrome P450 1A1 (CYP1A1). In addition, functional AhR was required for S. epidermidis-mediated induction of IL-1β expression in keratinocytes. AhR-dependent gene induction of IL-1β and CYP1A1 was mediated by factor(s) < 2 kDa secreted by S. epidermidis. Blockade of the AhR in a 3D organotypic skin equivalent infected with S. epidermidis attenuated the S. epidermidis-induced CYP1A1 and IL-1β expression. Moreover, S. epidermidis also induced expression of IL-1α and of the antimicrobial peptide human β-defensin-3 in an AhR-dependent manner in a 3D skin equivalent. An increased outgrowth of S. epidermidis on the surface of skin explants treated with a specific AhR inhibitor further indicate a pivotal role of the AhR in mediating an epidermal defense response. Taken together, our data expand the role of the AhR in innate immunity and support a previously unappreciated contribution for the AhR in cutaneous defense.

Kalinin: A new epithelial basement membrane adhesion molecule

1991 ◽  
Vol 49 ◽  
pp. 178-179
Author(s):  
Douglas R. Keene ◽  
Gregory P. Lunstrum ◽  
Patricia Rousselle ◽  
Robert E. Burgeson
Keyword(s):  
Basement Membrane ◽  
Culture Media ◽  
Polyacrylamide Gel Electrophoresis ◽  
Human Keratinocytes ◽  
Positive Staining ◽  
Human Amnion ◽  
Epithelial Basement Membrane ◽  
Type Vii Collagen ◽  
Keratinocyte Cell ◽  
Epithelial Basement

A mouse monoclonal antibody produced from collagenase digests of human amnion was used by LM and TEM to study the distribution and ultrastructural features of an antigen present in epithelial tissues and in cultured human keratinocytes, and by immunoaffinity chromatography to partially purify the antigen from keratinocyte cell culture media.By immunofluorescence microscopy, the antigen displays a tissue distribution similar to type VII collagen; positive staining of the epithelial basement membrane is seen in skin, oral mucosa, trachea, esophagus, cornea, amnion and lung. Images from rotary shadowed preparations isolated by affinity chromatography demonstrate a population of rod-like molecules 107 nm in length, having pronounced globular domains at each end. Polyacrylamide gel electrophoresis suggests that the size of this molecule is approximately 440kDa, and that it is composed of three nonidentical chains disulfide bonded together.

How do histone modifications contribute to transgenerational epigenetic inheritance in C. elegans?

2020 ◽  
Vol 48 (3) ◽  
pp. 1019-1034 ◽  
Author(s):  
Rachel M. Woodhouse ◽  
Alyson Ashe
Keyword(s):  
Histone Modifications ◽  
Molecular Mechanisms ◽  
Epigenetic Inheritance ◽  
Nematode Caenorhabditis Elegans ◽  
Histone Methyltransferases ◽  
Transgenerational Epigenetic Inheritance ◽  
C Elegans ◽  
Recent Developments ◽  
Gene Regulatory

Gene regulatory information can be inherited between generations in a phenomenon termed transgenerational epigenetic inheritance (TEI). While examples of TEI in many animals accumulate, the nematode Caenorhabditis elegans has proven particularly useful in investigating the underlying molecular mechanisms of this phenomenon. In C. elegans and other animals, the modification of histone proteins has emerged as a potential carrier and effector of transgenerational epigenetic information. In this review, we explore the contribution of histone modifications to TEI in C. elegans. We describe the role of repressive histone marks, histone methyltransferases, and associated chromatin factors in heritable gene silencing, and discuss recent developments and unanswered questions in how these factors integrate with other known TEI mechanisms. We also review the transgenerational effects of the manipulation of histone modifications on germline health and longevity.

Mesophyll conductance: the leaf corridors for photosynthesis

2020 ◽  
Vol 48 (2) ◽  
pp. 429-439 ◽  
Author(s):  
Jorge Gago ◽  
Danilo M. Daloso ◽  
Marc Carriquí ◽  
Miquel Nadal ◽  
Melanie Morales ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Current Knowledge ◽  
Main Role ◽  
Mesophyll Conductance ◽  
Future Studies ◽  
Cell Structures ◽  
Leaf Tissues ◽  
Change Framework ◽  
Chloroplast Stroma

Besides stomata, the photosynthetic CO2 pathway also involves the transport of CO2 from the sub-stomatal air spaces inside to the carboxylation sites in the chloroplast stroma, where Rubisco is located. This pathway is far to be a simple and direct way, formed by series of consecutive barriers that the CO2 should cross to be finally assimilated in photosynthesis, known as the mesophyll conductance (gm). Therefore, the gm reflects the pathway through different air, water and biophysical barriers within the leaf tissues and cell structures. Currently, it is known that gm can impose the same level of limitation (or even higher depending of the conditions) to photosynthesis than the wider known stomata or biochemistry. In this mini-review, we are focused on each of the gm determinants to summarize the current knowledge on the mechanisms driving gm from anatomical to metabolic and biochemical perspectives. Special attention deserve the latest studies demonstrating the importance of the molecular mechanisms driving anatomical traits as cell wall and the chloroplast surface exposed to the mesophyll airspaces (Sc/S) that significantly constrain gm. However, even considering these recent discoveries, still is poorly understood the mechanisms about signaling pathways linking the environment a/biotic stressors with gm responses. Thus, considering the main role of gm as a major driver of the CO2 availability at the carboxylation sites, future studies into these aspects will help us to understand photosynthesis responses in a global change framework.

A ‘Jurist-linguistic’ Reading of the wuḍūʾ Verse (Q. 5:6)

2010 ◽  
Vol 12 (1-2) ◽  
pp. 313-282
Author(s):  
ʿAbd al-ʿAzīz Mūsā
Keyword(s):  
The Third

This article sheds light on the role of grammar in understanding legislative texts, with reference to the wuḍūʾ verse (Q. 5:6). The first section deals with the issue of washing the elbows along with the feet as part of ritual ablution, and lists the various interpretations of the preposition ilā in the aya, and discusses the grammatical theory used by different fuqahāʾ to support their arguments. The second section tackles how much of the head should be rubbed in ritual ablution, with regard to the use of the preposition bi- in the phrase bi-ruʾūsikum, while the third focuses on the two readings of the phrase arjulakum/arjulikum (‘your feet’) and on passing legislative judgement on whether the feet be washed or just rubbed. The study concludes that lugha and fiqh theory are of mutual importance and together help to clarify legislative judgements, and, on this basis, that jurists should not pass any legislative judgement without referring to language.

Minangkabau Language Maintenance by the Association of Sei Jaring Community in Medan

2014 ◽  
Vol 11 (2) ◽  
Author(s):  
Yenita Uswar ◽  
Amrin Saragih ◽  
Tina Mariany Arifin
Keyword(s):  
Qualitative Research ◽  
Data Analysis ◽  
Language Maintenance ◽  
Young Generation ◽  
Third Generation ◽  
The Third ◽  
Danger Level

The objectives of this qualitative research were (1) to identify the factors that affect the Minangkabau language (ML) maintenance in Medan, (2) to discover the parents’ efforts in maintaining ML in Medan and (3) to find out the reason why the speakers have to maintain ML. The souree of data is the nembers of the Association of Sei Jaring Community (Ikatan Warga Sei Jaring: IWS) in Medan. The sample was 10 families including 10 parents and their children. The instruments of this study are a questionnaire and an interview. The questionnaire was used to answer the factors affected the maintenance of ML and how factors affected the maintenance of ML. The interview was used to discover the influence why Minangkabau’s people have to maintain ML. There are four factors in ML maintenance, the parents’ role, the role of family, the intramarriage and homeland visits. After distributing questionnaire and did some interviews it is found that IWS especially for the third generation (children) has the danger level in ML when they communicate to each other. Meanwhile, the data analysis also shows that both fathers and mothers communicate to each other with ML. This condition occurred because of the influence of the environment. Parents have to keep communication and teaching Minangkabau language continuously to their children. so, the young generation can keep the existence of ML for their future. Keywords: Minangkabau Language Maintenance, parents’ efforts, the young generation.

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