In certain maize genotypes, called "null," beta-glucosidase does not enter gels and therefore cannot be detected on zymograms after electrophoresis. Such genotypes were originally thought to be homozygous for a null allele at the glu1 gene and thus devoid of enzyme. We have shown that a beta-glucosidase-aggregating factor (BGAF) is responsible for the "null" phenotype. BGAF is a chimeric protein consisting of two distinct domains: the disease response or "dirigent" domain and the jacalin-related lectin (JRL) domain. First, it was not known whether the lectin domain in BGAF is functional. Second, it was not known which of the two BGAF domains is involved in beta-glucosidase binding and aggregation. To this end, we purified BGAF to homogeneity from a maize null inbred line called H95. The purified protein gave a single band on SDS-PAGE, and the native protein was a homodimer of 32-kDa monomers. Native and recombinant BGAF (produced in Escherichia coli) agglutinated rabbit erythrocytes, and various carbohydrates and glycoproteins inhibited their hemagglutination activity. Sugars did not have any effect on the binding of BGAF to the beta-glucosidase isozyme 1 (Glu1), and the BGAF-Glu1 complex could still bind lactosyl-agarose, indicating that the sugar-binding site of BGAF is distinct from the beta-glucosidase-binding site. Neither the dirigent nor the JRL domains alone (produced separately in E. coli) produced aggregates of Glu1 based on results from pull-down assays. However, gel shift and competitive binding assays indicated that the JRL domain binds beta-glucosidase without causing it to aggregate. These results with those from deletion mutagenesis and replacement of the JRL domain of a BGAF homolog from sorghum, which does not bind Glu1, with that from maize allowed us to conclude that the JRL domain of BGAF is responsible for its lectin and beta-glucosidase binding and aggregating activities.
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http://dx.doi.org/10.1074/jbc.M607417200 | DOI Listing |
J Med Genet
December 2024
Institute of Neuroanatomy, Medical Faculty, University of Bonn, Bonn, Germany.
Background: Previous studies in mouse, and zebrafish embryos show strong expression in progenitor cells of neuronal and neural crest tissues suggesting its involvement in neural crest specification. However, the role of human transcription factor activator protein 2 ( in human embryonic central nervous system (CNS), orofacial and maxillofacial development is unknown.
Methods: Through a collaborative work, exome survey was performed in families with congenital CNS, orofacial and maxillofacial anomalies.
Nature
January 2025
Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA, USA.
Somatic alterations in the oncogenic kinase AKT1 have been identified in a broad spectrum of solid tumours. The most common AKT1 alteration replaces Glu17 with Lys (E17K) in the regulatory pleckstrin homology domain, resulting in constitutive membrane localization and activation of oncogenic signalling. In clinical studies, pan-AKT inhibitors have been found to cause dose-limiting hyperglycaemia, which has motivated the search for mutant-selective inhibitors.
View Article and Find Full Text PDFAm J Hum Genet
November 2024
Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Section of Neurology and Developmental Neuroscience, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA; Texas Children's Hospital, Houston, TX 77030, USA. Electronic address:
Biomolecules
October 2024
Department of Surgical and Interventional Sciences, McGill University, Montreal, QC H3T 1E2, Canada.
Genome Med
September 2024
Andalusian Center for Developmental Biology (CABD), Junta de Andalucia - Universidad Pablo de Olavide (UPO) - Consejo Superior de Investigaciones Cientificas (CSIC), Seville, Spain.
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