Blackjack, a novel protein associated with microtubules in embryonic neurons

1996 ◽  
Vol 109 (6) ◽  
pp. 1497-1507
Author(s):  
K.R. Zachow ◽  
D. Bentley

Microtubule-associated proteins can influence the organization, stability and dynamics of microtubules. We characterize a novel protein that associates with microtubules as assessed by immunofluorescence, immunoelectron microscopy, and co-sedimentation. The protein is expressed heavily in embryonic neurons and, to a lesser extent, in epithelial and mesodermal cells. The cDNA sequence predicts a protein of 1,547 amino acids and approximately 170 kDa. Immunoblot of embryo lysate demonstrates bands of approximately 240 and 260 kDa. The predicted amino acid sequence contains 77 potential serine/threonine phosphorylation sites. A distinctive feature is a predicted alpha-helical central domain comprising 21 identical repeats of an 11 amino acid sequence (PLEELRKDAAE). The protein is thermostable and has two major charge-domains: the amino-terminal 80% has an estimated pI of 4.0 and the carboxy-terminal 20%, a pI of 12.2. The protein shares several general biochemical and molecular features of MAPs, but its sequence is not similar to that of any described MAP.

2001 ◽  
Vol 183 (14) ◽  
pp. 4183-4189 ◽  
Author(s):  
Dinene L. Crater ◽  
Charles P. Moran

ABSTRACT Proteins that have a structure similar to those of LuxR and FixJ comprise a large subfamily of transcriptional activator proteins. Most members of the LuxR-FixJ family contain a similar amino-terminal receiver domain linked by a small region to a carboxy-terminal domain that contains an amino acid sequence similar to the helix-turn-helix (HTH) motif found in other DNA-binding proteins. GerE fromBacillus subtilis is the smallest member of the LuxR-FixJ family. Its 74-amino-acid sequence is similar over its entire length to the DNA binding region of this protein family, including the HTH motif. Therefore, GerE provides a simple model for studies of the role of this HTH domain in DNA binding. Toward this aim, we sought to identify the amino acids within this motif that are important for the specificity of binding to DNA. We examined the effects of single base pair substitutions in the high-affinity GerE binding site on thesigK promoter and found that nucleotides at positions +2, +3, and +4 relative to the transcription start site on thesigK promoter are important for a high-affinity interaction with GerE. We next examined the effects of single alanine substitutions at two positions in the HTH region of GerE on binding to wild-type or mutant target sites. We found that the substitution of an alanine for the threonine at position 42 of GerE produced a protein that binds with equal affinity to two sites that differ by 1 bp, whereas wild-type GerE binds with different affinities to these two sites. These results provide evidence that the amino acyl residues in or near the putative HTH region of GerE and potentially other members of the LuxR-FixJ family determine the specificity of DNA binding.


1990 ◽  
Vol 269 (1) ◽  
pp. 61-64 ◽  
Author(s):  
I Correas ◽  
R Padilla ◽  
J Avila

The interaction of actin with a synthetic peptide which corresponds to one of the repeated tubulin-binding sites present in tau and MAP-2 (microtubule-associated protein 2) proteins has been analysed. The analysis, which uses affinity chromatography of G-actin on a column containing the synthetic peptide, and the co-sedimentation and co-localization of F-actin and the peptide (as determined by immunoelectron microscopy), indicates that the part of the amino acid sequence of tau involved in the binding of tubulin is also involved in actin binding.


1984 ◽  
Vol 99 (5) ◽  
pp. 1754-1760 ◽  
Author(s):  
K F Sullivan ◽  
D W Cleveland

The nucleotide sequence of a chicken genomic DNA segment containing the chicken beta 4 tubulin gene has been determined. The predicted amino acid sequence of beta 4 is surprisingly divergent from that of the chicken beta 2 gene that encodes the dominant neural beta tubulin. beta 4 differs from beta 2 at 36 residue positions and encodes a polypeptide that is four amino acids longer, yielding a divergence of 8.9% between the two beta tubulin isotypes. While many of the amino acid substitutions are conservative, several involve significant alteration in the physiochemical properties of the residue. Furthermore, the amino acid substitution positions are not randomly located within the primary sequence but are distinctly clustered: major divergence occurs in the carboxy-terminal region beyond residue 430 and within the second protein coding exon segments of the genes. In addition, large regions of absolute sequence conservation are also present. Certain sequences within the heterogeneous regions are conserved in other species, indicating that these regions are under positive evolutionary selection pressure and are therefore probably essential for some aspect of beta-tubulin function. These findings strongly suggest that regional amino acid sequence heterogeneity may play an important role in the establishment of functionally differentiated beta tubulin polypeptides.


1987 ◽  
Vol 262 (17) ◽  
pp. 8131-8137 ◽  
Author(s):  
S Miyazawa ◽  
H Hayashi ◽  
M Hijikata ◽  
N Ishii ◽  
S Furuta ◽  
...  

1992 ◽  
Vol 12 (2) ◽  
pp. 598-608
Author(s):  
J D Chen ◽  
C S Chan ◽  
V Pirrotta

The zeste gene product is involved in two types of genetic effects dependent on chromosome pairing: transvection and the zeste-white interaction. Comparison of the predicted amino acid sequence with that of the Drosophila virilis gene shows that several blocks of amino acid sequence have been very highly conserved. One of these regions corresponds to the DNA binding domain. Site-directed mutations in this region indicate that a sequence resembling that of the homeodomain DNA recognition helix is essential for DNA binding activity. The integrity of an amphipathic helical region is also essential for binding activity and is likely to be responsible for dimerization of the DNA binding domain. Another very strongly conserved domain of zeste is the C-terminal region, predicted to form a long helical structure with two sets of heptad repeats that constitute two long hydrophobic ridges at opposite ends and on opposite faces of the helix. We show that this domain is responsible for the extensive aggregation properties of zeste that are required for its role in transvection phenomena. A model is proposed according to which the hydrophobic ridges induce the formation of open-ended coiled-coil structures holding together many hundreds of zeste molecules and possibly anchoring these complexes to other nuclear structures.


2011 ◽  
Vol 39 (1) ◽  
pp. 116-121 ◽  
Author(s):  
Rosalie P.C. Driessen ◽  
Remus Th. Dame

Architectural proteins play an important role in compacting and organizing the chromosomal DNA in all three kingdoms of life (Eukarya, Bacteria and Archaea). These proteins are generally not conserved at the amino acid sequence level, but the mechanisms by which they modulate the genome do seem to be functionally conserved across kingdoms. On a generic level, architectural proteins can be classified based on their structural effect as DNA benders, DNA bridgers or DNA wrappers. Although chromatin organization in archaea has not been studied extensively, quite a number of architectural proteins have been identified. In the present paper, we summarize the knowledge currently available on these proteins in Crenarchaea. By the type of architectural proteins available, the crenarchaeal nucleoid shows similarities with that of Bacteria. It relies on the action of a large set of small, abundant and generally basic proteins to compact and organize their genome and to modulate its activity.


2001 ◽  
Vol 85 (03) ◽  
pp. 470-474 ◽  
Author(s):  
Kevin Siebenlist ◽  
Stephen Brennan ◽  
Trudy Holyst ◽  
Michael Mosesson ◽  
David Meh

SummaryHuman fibrin has a low affinity thrombin binding site in its E domain and a high affinity binding site in the carboxy-terminal region of its variant ’ chain (’408-427). Comparison of the ’ amino acid sequence (VRPEHPAETEYDSLYPEDDL) with other protein sequences known to bind to thrombin exosites such as those in GPIb , the platelet thrombin receptor, thrombomodulin, and hirudin suggests no homology or consensus sequences, but Glu and Asp enrichment are common to all. Tyrosine sulfation in these sequences enhances thrombin exosite binding, but this has not been uniformly investigated. The fibrinogen ’ chain mass determined by electrospray ionization mass spectrometry, was 50,549 Da, a value 151 Da greater than predicted from its amino acid/carbohydrate sequence. Since each sulfate group increases mass by 80 Da, this indicates that both tyrosines at 418 and 422 are sulfated. A series of overlapping ’ peptides was prepared for evaluation of their inhibition of 125I-labeled PPACK-thrombin binding to fibrin. ’414-427 was as effective an inhibitor as ’408-427 and its binding affinity was dependent on all carboxy-terminal residues. Mono Tyr-sulfated peptides were prepared by substituting non-sulfatable Phe for Tyr at ’ 418 or 422. Sulfation at either Tyr residue increased binding competition compared with non-sulfated peptides, but was less effective than doubly sulfated peptides, which had 4 to 8-fold greater affinity. The reverse ’ peptide or the forward sequence with repositioned Tyr residues did not compete well for thrombin binding, indicating that the positions of charged residues are important for thrombin binding affinity


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