scholarly journals WASp is required for the correct temporal morphogenesis of rhabdomere microvilli

2004 ◽  
Vol 164 (3) ◽  
pp. 417-426 ◽  
Author(s):  
Andrew C. Zelhof ◽  
Robert W. Hardy
Keyword(s):  
Drosophila Melanogaster ◽  
Brush Border ◽  
Molecular Basis ◽  
Apical Surface ◽  
Wiskott Aldrich Syndrome ◽  
Syndrome Protein

Microvilli are actin-based fingerlike membrane projections that form the basis of the brush border of enterocytes and the Drosophila melanogaster photoreceptor rhabdomere. Although many microvillar cytoskeletal components have been identified, the molecular basis of microvillus formation is largely undefined. Here, we report that the Wiskott-Aldrich syndrome protein (WASp) is necessary for rhabdomere microvillus morphogenesis. We show that WASp accumulates on the photoreceptor apical surface before microvillus formation, and at the time of microvillus initiation WASp colocalizes with amphiphysin and moesin. The loss of WASp delays the enrichment of F-actin on the apical photoreceptor surface, delays the appearance of the primordial microvillar projections, and subsequently leads to malformed rhabdomeres.

Wiskott-Aldrich Syndrome

2021 ◽  
Author(s):  
Saeed Sepehrnia
Keyword(s):  
Molecular Basis ◽  
Hematopoietic Cell Transplantation ◽  
Diagnostic Tools ◽  
Missense Mutations ◽  
Primary Immunodeficiency Disorder ◽  
Wiskott Aldrich Syndrome ◽  
Immunodeficiency Disorder ◽  
Wide Range ◽  
Clinical Disorders ◽  
Syndrome Protein

The Wiskott-Aldrich syndrome (WAS) could be a rare X-linked primary immunodeficiency disorder characterized by recurrent infections, eczema, and bleeding following thrombocytopenia. Despite the rarity of this syndrome, today our understanding of the cellular and molecular basis of the pathogenesis of this disease has increased and it’s well established that this disorder encompasses a wide range of clinical disorders including immunodeficiency, atopy, autoimmunity, and cancer. Wiskott–Aldrich Syndrome protein (WASP) mutations are located throughout the gene and inhibit or regulate the conventional function of WASP. Thus classic WAS occurs when WASP is absent, X-linked thrombocytopenia when mutated WASP is expressed, and X-linked neutropenia when missense mutations occur within the Cdc42-binding site. Developments within the use of diagnostic tools, supportive care, and advances in allogeneic hematopoietic cell transplantation have remarkably reduced the mortality related to this disorder. Besides, gene therapy has provided optimistic perspectives on the treatment approaches of those patients.

scholarly journals The nuclear receptor HNF4 drives a brush border gene program conserved across murine intestine, kidney, and embryonic yolk sac

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Lei Chen ◽  
Shirley Luo ◽  
Abigail Dupre ◽  
Roshan P. Vasoya ◽  
Aditya Parthasarathy ◽  
...  
Keyword(s):  
Brush Border ◽  
Regulatory Networks ◽  
Critical Role ◽  
Yolk Sac ◽  
Apical Surface ◽  
Transcriptional Regulatory Networks ◽  
Chromatin Looping ◽  
Multiple Organs ◽  
Transcriptional Regulatory ◽  
Transcriptional Regulatory Mechanisms

AbstractThe brush border is comprised of microvilli surface protrusions on the apical surface of epithelia. This specialized structure greatly increases absorptive surface area and plays crucial roles in human health. However, transcriptional regulatory networks controlling brush border genes are not fully understood. Here, we identify that hepatocyte nuclear factor 4 (HNF4) transcription factor is a conserved and important regulator of brush border gene program in multiple organs, such as intestine, kidney and yolk sac. Compromised brush border gene signatures and impaired transport were observed in these tissues upon HNF4 loss. By ChIP-seq, we find HNF4 binds and activates brush border genes in the intestine and kidney. H3K4me3 HiChIP-seq identifies that HNF4 loss results in impaired chromatin looping between enhancers and promoters at gene loci of brush border genes, and instead enhanced chromatin looping at gene loci of stress fiber genes in the intestine. This study provides comprehensive transcriptional regulatory mechanisms and a functional demonstration of a critical role for HNF4 in brush border gene regulation across multiple murine epithelial tissues.

scholarly journals The Novel Adaptor Protein, Mti1p, and Vrp1p, a Homolog of Wiskott-Aldrich Syndrome Protein-Interacting Protein (WIP), May Antagonistically Regulate Type I Myosins in Saccharomyces cerevisiae

Genetics ◽  
2002 ◽  
Vol 160 (3) ◽  
pp. 923-934
Author(s):  
Junko Mochida ◽  
Takaharu Yamamoto ◽  
Konomi Fujimura-Kamada ◽  
Kazuma Tanaka
Keyword(s):  
Adaptor Protein ◽  
Actin Binding ◽  
Temperature Sensitive ◽  
Null Mutation ◽  
Type I ◽  
Cortical Actin ◽  
Tail Region ◽  
Interacting Protein ◽  
Wiskott Aldrich Syndrome ◽  
Syndrome Protein

Abstract Type I myosins in yeast, Myo3p and Myo5p (Myo3/5p), are involved in the reorganization of the actin cytoskeleton. The SH3 domain of Myo5p regulates the polymerization of actin through interactions with both Las17p, a homolog of mammalian Wiskott-Aldrich syndrome protein (WASP), and Vrp1p, a homolog of WASP-interacting protein (WIP). Vrp1p is required for both the localization of Myo5p to cortical patch-like structures and the ATP-independent interaction between the Myo5p tail region and actin filaments. We have identified and characterized a new adaptor protein, Mti1p (Myosin tail region-interacting protein), which interacts with the SH3 domains of Myo3/5p. Mti1p co-immunoprecipitated with Myo5p and Mti1p-GFP co-localized with cortical actin patches. A null mutation of MTI1 exhibited synthetic lethal phenotypes with mutations in SAC6 and SLA2, which encode actin-bundling and cortical actin-binding proteins, respectively. Although the mti1 null mutation alone did not display any obvious phenotype, it suppressed vrp1 mutation phenotypes, including temperature-sensitive growth, abnormally large cell morphology, defects in endocytosis and salt-sensitive growth. These results suggest that Mti1p and Vrp1p antagonistically regulate type I myosin functions.

NMR Analyses of the Activation of the Arp2/3 Complex by Neuronal Wiskott−Aldrich Syndrome Protein†

Biochemistry ◽  
2005 ◽  
Vol 44 (46) ◽  
pp. 15247-15256 ◽  
Author(s):  
Mara Kreishman-Deitrick ◽  
Erin D. Goley ◽  
Lyle Burdine ◽  
Carilee Denison ◽  
Coumaran Egile ◽  
...  
Keyword(s):  
Wiskott Aldrich Syndrome ◽  
Syndrome Protein

scholarly journals Two Atypical Enteropathogenic Escherichia coli Strains Induce the Production of Secreted and Membrane-Bound Mucins To Benefit Their Own Growth at the Apical Surface of Human Mucin-Secreting Intestinal HT29-MTX Cells

2010 ◽  
Vol 78 (3) ◽  
pp. 927-938 ◽  
Author(s):  
Mônica A. M. Vieira ◽  
Tânia A. T. Gomes ◽  
Antonio J. P. Ferreira ◽  
Terezinha Knöbl ◽  
Alain L. Servin ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Membrane ◽  
Brush Border ◽  
Apical Surface ◽  
Enteropathogenic Escherichia Coli ◽  
Typical Epec ◽  
Membrane Bound

ABSTRACT In rabbit ligated ileal loops, two atypical enteropathogenic Escherichia coli (aEPEC) strains, 3991-1 and 0421-1, intimately associated with the cell membrane, forming the characteristic EPEC attachment and effacement lesion of the brush border, induced a mucous hypersecretion, whereas typical EPEC (tEPEC) strain E2348/69 did not. Using cultured human mucin-secreting intestinal HT29-MTX cells, we demonstrate that apically aEPEC infection is followed by increased production of secreted MUC2 and MUC5AC mucins and membrane-bound MUC3 and MUC4 mucins. The transcription of the MUC5AC and MUC4 genes was transiently upregulated after aEPEC infection. We provide evidence that the apically adhering aEPEC cells exploit the mucins' increased production since they grew in the presence of membrane-bound mucins, whereas tEPEC did not. The data described herein report a putative new virulence phenomenon in aEPEC.

scholarly journals Fyn and PTP-PEST–mediated Regulation of Wiskott-Aldrich Syndrome Protein (WASp) Tyrosine Phosphorylation Is Required for Coupling T Cell Antigen Receptor Engagement to WASp Effector Function and T Cell Activation

2004 ◽  
Vol 199 (1) ◽  
pp. 99-112 ◽  
Author(s):  
Karen Badour ◽  
Jinyi Zhang ◽  
Fabio Shi ◽  
Yan Leng ◽  
Michael Collins ◽  
...  
Keyword(s):  
T Cell ◽  
Tyrosine Phosphorylation ◽  
T Cell Activation ◽  
Actin Polymerization ◽  
Cell Activation ◽  
Synapse Formation ◽  
Tyrosine Phosphatase ◽  
Structural Constraints ◽  
Wiskott Aldrich Syndrome ◽  
Syndrome Protein

Involvement of the Wiskott-Aldrich syndrome protein (WASp) in promoting cell activation requires its release from autoinhibitory structural constraints and has been attributed to WASp association with activated cdc42. Here, however, we show that T cell development and T cell receptor (TCR)-induced proliferation and actin polymerization proceed normally in WASp−/− mice expressing a WASp transgene lacking the cdc42 binding domain. By contrast, mutation of tyrosine residue Y291, identified here as the major site of TCR-induced WASp tyrosine phosphorylation, abrogated induction of WASp tyrosine phosphorylation and its effector activities, including nuclear factor of activated T cell transcriptional activity, actin polymerization, and immunological synapse formation. TCR-induced WASp tyrosine phosphorylation was also disrupted in T cells lacking Fyn, a kinase shown here to bind, colocalize with, and phosphorylate WASp. By contrast, WASp was tyrosine dephosphorylated by protein tyrosine phosphatase (PTP)-PEST, a tyrosine phosphatase shown here to interact with WASp via proline, serine, threonine phosphatase interacting protein (PSTPIP)1 binding. Although Fyn enhanced WASp-mediated Arp2/3 activation and was required for synapse formation, PTP-PEST combined with PSTPIP1 inhibited WASp-driven actin polymerization and synapse formation. These observations identify key roles for Fyn and PTP-PEST in regulating WASp and imply that inducible WASp tyrosine phosphorylation can occur independently of cdc42 binding, but unlike the cdc42 interaction, is absolutely required for WASp contributions to T cell activation.

scholarly journals Wiskott–Aldrich syndrome protein (WASP) is a tumor suppressor in T cell lymphoma

2018 ◽  
Vol 25 (1) ◽  
pp. 130-140 ◽  
Author(s):  
Matteo Menotti ◽  
Chiara Ambrogio ◽  
Taek-Chin Cheong ◽  
Chiara Pighi ◽  
Ines Mota ◽  
...  
Keyword(s):  
T Cell ◽  
Tumor Suppressor ◽  
Cell Lymphoma ◽  
T Cell Lymphoma ◽  
Wiskott Aldrich Syndrome ◽  
Syndrome Protein
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