Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0393754 (HSA)
 2,996 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Large nuclear proteins must possess a signal sequence to pass through the nuclear pores. Using an in vitro system, we have been able experimentally to dissect nuclear protein transport into two distinct steps: binding and translocation. In the absence of ATP, we observe a binding of nuclear proteins to the pore that is signal sequence-dependent. Translocation through the pore, on the other hand, strictly requires ATP. These steps, visualized in the fluorescence and electron microscopes, were observed both with a natural nuclear protein, nucleoplasmin, and a synthetic nuclear protein, composed of the signal sequence of SV40 T antigen coupled to HSA. When a mutant signal sequence was coupled to HSA, neither transport nor binding were observed, indicating that both result from the presence of a functional signal sequence. An inhibitor of transport, the lectin WGA, also arrested nuclear proteins in a bound state at the cytoplasmic face of the pore. Therefore, only the translocation step is sensitive to the inhibitor WGA, which is known to bind specifically to proteins of the nuclear pore.
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PMID:Nuclear import can be separated into distinct steps in vitro: nuclear pore binding and translocation. 334 67

The multiprotein complexes involved in active dis-ruption of chromatin structure, homologous to yeast SWI/SNF complex, have been described for human and Drosophila cells. In all SWI/SNF-class complexes characterised so far, one of the key components is the SNF5-type protein. Here we describe the isolation of a plant (Arabidopsis thaliana ) cDNA encoding a 27 kDa protein which we named BSH, with high homology to yeast SNF5p and its human (INI1) and Drosophila (SNR1) counterparts as well as to other putative SNF5-type proteins from Caenorhabditis elegans, fish and yeast. With 240 amino acids, the Arabidopsis BSH is the smallest SNF5-type protein so far identified. When expressed in Saccharomyces cerevisiae, the gene for BSH partially complements the snf5 mutation. BSH is, however, unable to activate transcription in yeast when tethered to DNA. The gene for BSH occurs in single copy in the Arabidopsis genome and is ubiquitously expressed in the plant. Analysis of the whole cell and nuclear protein extracts with antibodies against recombinant BSH indicates that the protein is localised in nuclei. Transgenic Arabidopsis plants with markedly decreased physiological level of the BSH mRNA, resulting from the expression of antisense messenger, are viable but exhibit a distinctive phenotype characterised by bushy growth and flowers that are unable to produce seeds.
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PMID:Identification and analysis of the Arabidopsis thaliana BSH gene, a member of the SNF5 gene family. 1032 30