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Several Cellular Processes (several + cellular_process)

Distribution by Scientific Domains

Medical Sciences	40%
Chemistry	40%

Selected Abstracts

Analysis of the interaction of 16S rRNA and cytoplasmic membrane with the C-terminal part of the Streptococcus pneumoniae Era GTPase

FEBS JOURNAL, Issue 21 2001
Julie Qi Hang
Era, an essential GTPase, plays a regulatory role in several cellular processes. The Era protein of Streptococcus pneumoniae has recently been shown to bind to 16S rRNA and the cytoplasmic membrane. However, exact locations of Era responsible for RNA- and membrane-binding were unknown. To identify the regions in Era that interact with the RNA and membrane, the C-terminal part of S. pneumoniae Era was systematically deleted while the N-terminal part, responsible for the GTPase activity of the protein, was kept intact. The resulting truncated Era proteins were purified and characterized. The C-terminal deletion of 9 or 19 amino-acid residues did not affect 16S rRNA-binding activity while further deletions of the C-terminus (29,114 amino-acid residues) abolished the activity. These results indicate that the integrity of the putative KH domain of Era, spanning the amino-acid residues between ,,22,83 from the C-terminus, is required for 16S rRNA-binding. Furthermore, the Era proteins with a deletion up to 45 residues from the C-terminus retained membrane-binding activity, but longer deletions significantly reduced the activity. These results indicate that part of the putative KH domain is also required for membrane-binding. Thus, these results indicate for the first time that the regions critical for the membrane- and 16S rRNA-binding activities of Era overlap. The era gene with a deletion of 9 or 19 codons from its 3, terminus complemented an Escherishia coli mutant strain deficient in Era production whereas the genes with longer deletions failed to do so, thereby indicating that the KH domain is essential for Era function. Taken together, the results of this study indicate that the putative KH domain is required for 16S rRNA-binding activity and that part of the KH domain is also required for membrane-binding activity. The results also suggest that the interaction between Era and 16S rRNA is essential for bacterial growth. [source]

Properties of the hepatitis C virus core protein: a structural protein that modulates cellular processes

JOURNAL OF VIRAL HEPATITIS, Issue 1 2000
McLauchlan
The core protein of hepatitis C virus (HCV) is believed to form the capsid shell of virus particles. Maturation of the protein is achieved through cleavage by host cell proteases to give a product of 21 000 MW, which is found in tissue culture systems and sera from infected individuals. However, efficient propagation of the virus is not possible at present in tissue culture. Hence, studies have focused on the properties of the core protein and its possible role in pathologies associated with HCV infection. This review describes key features of the polypeptide and the status of current knowledge on its ability to influence several cellular processes. [source]

Genome-wide transcriptional profiling in human squamous cell carcinoma of the skin identifies unique tumor-associated signatures

THE JOURNAL OF DERMATOLOGY, Issue 5 2006
Vinnie P. KATHPALIA
ABSTRACT The elucidation of specific genetic changes associated with human cancer pathogenesis has focused efforts to relate such changes to the neoplastic phenotype. To further our understanding of the genetic basis of human squamous cell carcinoma (SCC) of the skin, this study used a genome-wide (12 627 sequences) approach to determine transcriptional signatures in lesional and nonlesional sites from five SCC patients. Several novel genes involving the p53 pathway, anti-apoptotic pathways, signal transduction, structural loss and DNA replication, including BCL2A1, MUC4, PTPN11 (SHP2) and FGF9, are upregulated in SCC and could warrant further study regarding their role in disease pathogenesis. SCC pathology is likely combinatorial in nature involving the compounded changes from several cellular processes. [source]

Direct inter-subdomain interactions switch between the closed and open forms of the Hsp70 nucleotide-binding domain in the nucleotide-free state

ACTA CRYSTALLOGRAPHICA SECTION D, Issue 3 2010
Meiri Shida
The 70,kDa heat-shock proteins (Hsp70s) are highly conserved chaperones that are involved in several cellular processes, such as protein folding, disaggregation and translocation. In this study, the crystal structures of the human Hsp70 nucleotide-binding domain (NBD) fragment were determined in the nucleotide-free state and in complex with adenosine 5,-(,,,-imido)triphosphate (AMPPNP). The structure of the nucleotide-free NBD fragment is similar to that of the AMPPNP-bound NBD fragment and is designated as the `closed form'. In the nucleotide-free NBD fragment the closed form is intrinsically supported through interactions between Tyr15, Lys56 and Glu268 which connect subdomains IA, IB and IIB at the centre of the protein. Interaction with the substrate-binding domain (SBD) of Hsp70 or the BAG domain of BAG1 impairs this subdomain connection and triggers the rotation of subdomain IIA around a hydrophobic helix from subdomain IA. The subdomain rotation is limited by Asp199 and Asp206 from subdomain IIA and clearly defines the open form of the NBD. The open form is further stabilized by a new interaction between Gly230 from subdomain IIB and Ser340 from subdomain IIA. The structure of the NBD in the nucleotide-free state is determined by switching of the inter-subdomain interactions. [source]

Development of cortical GABAergic circuits and its implications for neurodevelopmental disorders

CLINICAL GENETICS, Issue 1 2007
G Di Cristo
GABAergic interneurons powerfully control the function of cortical networks. In addition, they strongly regulate cortical development by modulating several cellular processes such as neuronal proliferation, migration, differentiation and connectivity. Not surprisingly, aberrant development of GABAergic circuits has been implicated in many neurodevelopmental disorders including schizophrenia, autism and Tourette's syndrome. Unfortunately, efforts directed towards the comprehension of the mechanisms regulating GABAergic circuits formation and function have been impaired by the strikingly heterogeneity, both at the morphological and functional level, of GABAergic interneurons. Recent technical advances, including the improvement of interneurons-specific labelling techniques, have started to reveal the basic principles underlying this process. This review summarizes recent findings on the mechanisms underlying the construction of GABAergic circuits in the cortex, with a particular focus on potential implications for brain diseases with neurodevelopmental origin. [source]