scholarly journals The Carboxy-Terminal Region of apoA-I Is Required for the ABCA1-Dependent Formation of α-HDL But Not Preβ-HDL Particles in Vivo†

Biochemistry ◽  
2007 ◽  
Vol 46 (19) ◽  
pp. 5697-5708 ◽  
Author(s):  
Angeliki Chroni ◽  
Georgios Koukos ◽  
Adelina Duka ◽  
Vassilis I. Zannis
2000 ◽  
Vol 20 (6) ◽  
pp. 2285-2295 ◽  
Author(s):  
Yang Hong ◽  
Rosalind C. Lee ◽  
Victor Ambros

ABSTRACT During postembryonic development of Caenorhabditis elegans, the heterochronic gene lin-14 controls the timing of developmental events in diverse cell types. Three alternativelin-14 transcripts are predicted to encode isoforms of a novel nuclear protein that differ in their amino-terminal domains. In this paper, we report that the alternative amino-terminal domains of LIN-14 are dispensable and that a carboxy-terminal region within exons 9 to 13 is necessary and sufficient for in vivo LIN-14 function. A transgene capable of expressing only one of the three alternativelin-14 gene products rescues a lin-14 null mutation and is developmentally regulated by lin-4. This shows that the deployment of alternative lin-14 gene products is not critical for the ability of LIN-14 to regulate downstream genes in diverse cell types or for the in vivo regulation of LIN-14 level by lin-4. The carboxy-terminal region of LIN-14 contains an unusual expanded nuclear localization domain which is essential for LIN-14 function. These results support the view that LIN-14 controls developmental timing in C. elegans by regulating gene expression in the nucleus.


2003 ◽  
Vol 23 (24) ◽  
pp. 8934-8945 ◽  
Author(s):  
Sophie Magné ◽  
Sandrine Caron ◽  
Martine Charon ◽  
Marie-Christine Rouyez ◽  
Isabelle Dusanter-Fourt

ABSTRACT Signal transducer and activator of transcription 5 (STAT5) is activated by numerous cytokines that control blood cell development. STAT5 was also shown to actively participate in leukemogenesis. Among the target genes involved in cell growth, STAT5 had been shown to activate cyclin D1 gene expression. We now show that thrombopoietin-dependent activation of the cyclin D1 promoter depends on the integrity of a new bipartite proximal element that specifically binds STAT5A and -B transcription factors. We demonstrate that the stable recruitment of STAT5 to this element in vitro requires the integrity of an adjacent octamer element that constitutively binds the ubiquitous POU homeodomain protein Oct-1. We observe that cytokine-activated STAT5 and Oct-1 form a unique complex with the cyclin D1 promoter sequence. We find that STAT5 interacts with Oct-1 in vivo, following activation by different cytokines in various cellular contexts. This interaction involves a small motif in the carboxy-terminal region of STAT5 which, remarkably, is similar to an Oct-1 POU-interacting motif present in two well-known partners of Oct-1, namely, OBF-1/Bob and SNAP190. Our data offer new insights into the transcriptional regulation of the key cell cycle regulator cyclin D1 and emphasize the active roles of both STAT5 and Oct-1 in this process.


1996 ◽  
Vol 109 (6) ◽  
pp. 1471-1478 ◽  
Author(s):  
J.C. Zabala ◽  
A. Fontalba ◽  
J. Avila

Tubulins contain a glycine-rich loop, that has been implicated in microtubule dynamics by means of an intramolecular interaction with the carboxy-terminal region. As a further extension of the analysis of the role of the carboxy-terminal region in tubulin folding we have mutated the glycine-rich loop of tubulin subunits. An alpha-tubulin point mutant with a T150-->G substitution (the corresponding residue present in beta-tubulin) was able to incorporate into dimers and microtubules. On the other hand, four beta-tubulin point mutants, including the G148-->T substitution, did not incorporate into dimers, did not release monomers, but were able to form C900 and C300 complexes (intermediates in the process of tubulin folding). Three other mutants within this region (which approximately encompasses residues 137–152) were incapable of forming dimers and C300 complexes but gave rise to the formation of C900 complexes. These results suggest that tubulin goes through two sequential folding states during the folding process, first in association with TCP1-complexes (C900) prior to the transfer to C300 complexes. It is this second step that implies binding/hydrolysis of GTP, reinforcing our previous proposed model for tubulin folding and assembly.


1971 ◽  
Vol 133 (6) ◽  
pp. 1309-1324 ◽  
Author(s):  
Herbert Lindsley ◽  
Mart Mannik ◽  
Paul Bornstein

Immunological studies of rat skin collagen were carried out with a sensitive and quantitative radioimmunoassay. Hyperimmune rabbit antisera to rat skin collagen and isolated α2 chains were used. Iodine-labeled α chains and CNBr-produced peptides served as test antigens, and native collagen, α chains, and CNBr peptides were employed as inhibitors in the assay. The α1 and α2 chains were immunologically distinct. Although the α1 chain was not immunogenic, antibodies to α1 were detected in antisera to the intact collagen molecule. The major antigenic determinant of the α1 chain was located in α1-CB6 which constitutes the carboxy-terminal region of the chain. The α2 chain contained two non-cross-reacting antigenic determinants, one in the amino-terminal region (α2-CB1) and the other in the carboxy-terminal region (α2-CB5) of the chain. The native collagen molecule was less effective than isolated α chains in inhibiting binding of labeled peptides to antisera, indicating that antigenic determinants were less accessible in the triple helical molecule. These immunologic studies are consistent with preliminary comparative biochemical data which indicate that interspecies structural differences in collagen predominate at both the amino- and carboxy-terminal ends of the chains.


2001 ◽  
Vol 183 (23) ◽  
pp. 6961-6964 ◽  
Author(s):  
Hiroyasu Yamanaka ◽  
Hiroshi Izawa ◽  
Keinosuke Okamoto

ABSTRACT The Escherichia coli TolC acts as a channel tunnel in the transport of various molecules across the outer membrane. Partial-deletion studies of tolC revealed that the region extending from the 50th to the 60th amino acid residue from the carboxy terminus plays an important role in this transport activity of TolC.


1971 ◽  
Vol 49 (3) ◽  
pp. 372-375
Author(s):  
P. J. Anderson

The modification of the carboxy-terminal of sturgeon muscle aldolase with carboxypeptidase produces similar kinetic effects to those observed on modification of the rabbit muscle enzyme. The nature and molar ratios of amino acids released indicate that differences between the two enzymes occur in the carboxy-terminal region.


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