scholarly journals The importance of a potential phosphorylation site in enamelin on enamel formation

2017 ◽  
Vol 9 (11) ◽  
pp. e4-e4 ◽  
Author(s):  
Wen-Juan Yan ◽  
Pan Ma ◽  
Ye Tian ◽  
Jing-Ya Wang ◽  
Chun-Lin Qin ◽  
...  
Keyword(s):  
Phosphorylation Site ◽  
Enamel Formation ◽  
Potential Phosphorylation Site

scholarly journals A deletional frameshift mutation of the beta-spectrin gene associated with elliptocytosis in spectrin Tokyo (beta 220/216)

Blood ◽  
1992 ◽  
Vol 80 (8) ◽  
pp. 2115-2121 ◽  
Author(s):  
A Kanzaki ◽  
M Rabodonirina ◽  
Y Yawata ◽  
R Wilmotte ◽  
H Wada ◽  
...  
Keyword(s):  
Amino Acids ◽  
Genomic Dna ◽  
Frameshift Mutation ◽  
Stop Codon ◽  
Phosphorylation Site ◽  
Beta Chain ◽  
Potential Phosphorylation Site ◽  
Self Association ◽  
Beta Gene

Abstract A novel spectrin variant carrying a truncated beta-chain and designated Spectrin Tokyo (beta 220/216) is presented. It was associated with elliptocytosis and moderate uncompensated hemolysis. The dimer self- association was reduced. An increase of the alpha I 74-Kd fragment was detected upon partial trypsin digestion. Analysis of cDNA and genomic DNA showed a 1-base deletion in codon 2059 (GCC AGC-->GCA GCT; Ala-Ser-- >Ala-Ala) that belongs to exon X of spectrin beta-gene. A missense sequence extended down to (new) codon 2075. Serine 2060, a potential phosphorylation site, was replaced by alanine. The shortened beta-chain failed to undergo phosphorylation in vitro. Spectrin Tokyo shared the same stop codon, overlapping normal codons 2076 and 2077 (CTG AAA), as Spectrin Nice (beta 220/216), which is caused by a dinucleotide insertion in codon 2046 and contains 2076 amino acids. However, for some reason, Spectrin Tokyo had a lower incorporation level into the membrane than Spectrin Nice.

scholarly journals Bypass of Activation Loop Phosphorylation by Aspartate 836 in Activation of the Endoribonuclease Activity of Ire1

2017 ◽  
Vol 37 (16) ◽  
Author(s):  
Michael C. Armstrong ◽  
Sergej Šestak ◽  
Ahmed A. Ali ◽  
Hanan A. M. Sagini ◽  
Max Brown ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Phosphorylation Site ◽  
Spectrometric Analysis ◽  
Activation Loop ◽  
Unfolded Proteins ◽  
Potential Phosphorylation Site ◽  
Content Type ◽  
Mrna Induction ◽  
Better Than

ABSTRACT The bifunctional protein kinase-endoribonuclease Ire1 initiates splicing of the mRNA for the transcription factor Hac1 when unfolded proteins accumulate in the endoplasmic reticulum. Activation of Saccharomyces cerevisiae Ire1 coincides with autophosphorylation of its activation loop at S840, S841, T844, and S850. Mass spectrometric analysis of Ire1 expressed in Escherichia coli identified S837 as another potential phosphorylation site in vivo. Mutation of all five potential phosphorylation sites in the activation loop decreased, but did not completely abolish, splicing of HAC1 mRNA, induction of KAR2 and PDI1 mRNAs, and expression of a β-galactosidase reporter activated by Hac1i. Phosphorylation site mutants survive low levels of endoplasmic reticulum stress better than IRE1 deletions strains. In vivo clustering and inactivation of Ire1 are not affected by phosphorylation site mutants. Mutation of D836 to alanine in the activation loop of phosphorylation site mutants nearly completely abolished HAC1 splicing, induction of KAR2, PDI1, and β-galactosidase reporters, and survival of ER stress, but it had no effect on clustering of Ire1. By itself, the D836A mutation does not confer a phenotype. These data argue that D836 can partially substitute for activation loop phosphorylation in activation of the endoribonuclease domain of Ire1.

scholarly journals Molecular cloning of a novel N-terminal variant of annexin II from rat basophilic leukaemia cells

1994 ◽  
Vol 302 (2) ◽  
pp. 425-428 ◽  
Author(s):  
A L Upton ◽  
S E Moss
Keyword(s):  
Single Gene ◽  
Phosphorylation Site ◽  
Serine Phosphorylation ◽  
Annexin Ii ◽  
Cdna Clones ◽  
Potential Phosphorylation Site ◽  
Plasmid Library ◽  
Alternatively Spliced ◽  
High Level ◽  
Species Hybridization

Rat annexin II cDNA clones were isolated from a rat basophilic leukaemia cell plasmid library by cross-species hybridization with a mouse probe, and fully sequenced using the dideoxy-chain-termination method. Alignment of the derived amino-acid sequence with those of other mammalian annexin II species revealed a high level of conservation, characteristic of the annexin family of proteins. One of the cDNAs isolated contained an additional six nucleotides close to the N-terminus, lying in-frame and at a point corresponding to an intron/exon boundary in the human annexin II gene. As the two rat cDNAs were identical apart from the six nucleotide insert, it is likely that these represent alternatively spliced transcripts of a single gene, rather than the products of two separate genes. The six nucleotides encode serine-glutamine and therefore introduce an additional potential phosphorylation site into a region already containing one tyrosine and two serine phosphorylation sites. The discovery of this novel annexin II variant may have important implications both for p11 binding and for regulation of annexin II function by phosphorylation.

scholarly journals Phosphatidylinositol 3-Phosphate Indirectly Activates KCa3.1 via 14 Amino Acids in the Carboxy Terminus of KCa3.1

2006 ◽  
Vol 17 (1) ◽  
pp. 146-154 ◽  
Author(s):  
Shekhar Srivastava ◽  
Papiya Choudhury ◽  
Zhai Li ◽  
GongXin Liu ◽  
Vivek Nadkarni ◽  
...  
Keyword(s):  
Amino Acids ◽  
Biological Function ◽  
Phosphorylation Site ◽  
Chloride Secretion ◽  
Regulatory Subunit ◽  
Channel Activity ◽  
Potential Phosphorylation Site ◽  
Calmodulin Binding ◽  
Carboxy Terminal ◽  
Phosphatidylinositol 3

KCa3.1 is an intermediate conductance Ca2+-activated K+ channel that is expressed predominantly in hematopoietic cells, smooth muscle cells, and epithelia where it functions to regulate membrane potential, Ca2+ influx, cell volume, and chloride secretion. We recently found that the KCa3.1 channel also specifically requires phosphatidylinositol-3 phosphate [PI(3)P] for channel activity and is inhibited by myotubularin-related protein 6 (MTMR6), a PI(3)P phosphatase. We now show that PI(3)P indirectly activates KCa3.1. Unlike KCa3.1 channels, the related KCa2.1, KCa2.2, or KCa2.3 channels do not require PI(3)P for activity, suggesting that the KCa3.1 channel has evolved a unique means of regulation that is critical for its biological function. By making chimeric channels between KCa3.1 and KCa2.3, we identified a stretch of 14 amino acids in the carboxy-terminal calmodulin binding domain of KCa3.1 that is sufficient to confer regulation of KCa2.3 by PI(3)P. However, mutation of a single potential phosphorylation site in these 14 amino acids did not affect channel activity. These data together suggest that PI(3)P and these 14 amino acids regulate KCa3.1 channel activity by recruiting an as yet to be defined regulatory subunit that is required for Ca2+ gating of KCa3.1.

scholarly journals A deletional frameshift mutation of the beta-spectrin gene associated with elliptocytosis in spectrin Tokyo (beta 220/216)

Blood ◽  
1992 ◽  
Vol 80 (8) ◽  
pp. 2115-2121
Author(s):  
A Kanzaki ◽  
M Rabodonirina ◽  
Y Yawata ◽  
R Wilmotte ◽  
H Wada ◽  
...  
Keyword(s):  
Amino Acids ◽  
Genomic Dna ◽  
Frameshift Mutation ◽  
Stop Codon ◽  
Phosphorylation Site ◽  
Beta Chain ◽  
Potential Phosphorylation Site ◽  
Self Association ◽  
Beta Gene

A novel spectrin variant carrying a truncated beta-chain and designated Spectrin Tokyo (beta 220/216) is presented. It was associated with elliptocytosis and moderate uncompensated hemolysis. The dimer self- association was reduced. An increase of the alpha I 74-Kd fragment was detected upon partial trypsin digestion. Analysis of cDNA and genomic DNA showed a 1-base deletion in codon 2059 (GCC AGC-->GCA GCT; Ala-Ser-- >Ala-Ala) that belongs to exon X of spectrin beta-gene. A missense sequence extended down to (new) codon 2075. Serine 2060, a potential phosphorylation site, was replaced by alanine. The shortened beta-chain failed to undergo phosphorylation in vitro. Spectrin Tokyo shared the same stop codon, overlapping normal codons 2076 and 2077 (CTG AAA), as Spectrin Nice (beta 220/216), which is caused by a dinucleotide insertion in codon 2046 and contains 2076 amino acids. However, for some reason, Spectrin Tokyo had a lower incorporation level into the membrane than Spectrin Nice.

scholarly journals Relationship between RNA Lariat Debranching and Ty1 Element Retrotransposition

2003 ◽  
Vol 77 (23) ◽  
pp. 12795-12806 ◽  
Author(s):  
Laura A. Salem ◽  
Christopher L. Boucher ◽  
Thomas M. Menees
Keyword(s):  
Rnase Protection Assay ◽  
Phosphorylation Site ◽  
Single Amino Acid ◽  
Rnase Protection ◽  
Potential Phosphorylation Site ◽  
Rna Probes ◽  
Pcr Method ◽  
Rna Protection ◽  
Rna Accumulation ◽  
The Relationship

ABSTRACT The Saccharomyces cerevisiae DBR1 gene encodes a 2′-5′ phosphodiesterase that debranches intron RNA lariats following splicing. Yeast dbr1 mutants accumulate intron lariats and are also defective for mobility of the retrotransposons Ty1 and Ty3. We used a mutagenic PCR method to generate a collection of dbr1 mutant alleles to explore the relationship between the roles of DBR1 in transposition and debranching. Eight mutants defective for Ty1 transposition contained single amino acid changes in Dbr1p. Two mutations, G84A and N85D, are in a conserved phosphoesterase motif that is believed to be part of the active site of the enzyme, supporting a connection between enzymatic activity and Ty1 transposition. Two other mutations, Y68F and Y68D, occur at a potential phosphorylation site, and we have shown that Dbr1p is phosphorylated on tyrosine. We have developed an RNase protection assay to quantitate intron RNA accumulation in cells. The assay uses RNA probes that hybridize to ACT1 intron RNA. Protection patterns confirm that sequences from the 5′ end of the intron to the lariat branch point accumulate in dbr1 mutants in a branched (lariat) conformation. RNase protection assays indicate that all of the newly generated dbr1 mutant alleles are also deficient for debranching, further supporting a role for 2′-5′ phosphodiesterase activity in Ty1 transposition. A Ty1 element lacking most of its internal sequences transposes independently of DBR1. The existence of Dbr1p-dependent Ty1 sequences raises the possibility that Dbr1p acts on Ty1 RNA.

Characterization of human septin interactions

2011 ◽  
Vol 392 (8-9) ◽  
pp. 751-761 ◽  
Author(s):  
Kirstin Sandrock ◽  
Ingrid Bartsch ◽  
Susanne Bläser ◽  
Anja Busse ◽  
Eileen Busse ◽  
...  
Keyword(s):  
Large Scale ◽  
Cell Cycle Progression ◽  
Phosphorylation Site ◽  
Yeast Two Hybrid ◽  
Cycle Progression ◽  
Potential Phosphorylation Site ◽  
Interaction Partners ◽  
Two Hybrid

Abstract Septins constitute a group of GTP binding proteins that assemble into homo- and hetero-oligomeric complexes and filaments. These higher order septin structures are thought to function like scaffolds and/or diffusion barriers serving as spatial localizers for many proteins with key roles in cell polarity and cell cycle progression. In this study, we extensively characterized septin interaction partners using yeast two-hybrid and three-hybrid systems in addition to precipitation analyses in platelets. As a result, we identified human hetero-trimeric septin complexes on a large scale, which had been only postulated in the past. In addition, we illustrated roles of SEPT9 that might contribute to hetero-trimeric septin complex formation. SEPT9 can substitute for septins of the SEPT2 group and partially for SEPT7. Mutagenic analyses revealed that mutation of a potential phosphorylation site in SEPT7 (Y318) regulates the interaction with other septins. We identified several septin-septin interactions in platelets suggesting a regulatory role of diverse septin complexes in platelet function.

scholarly journals Effect of caspase cleavage-site phosphorylation on proteolysis

2003 ◽  
Vol 372 (1) ◽  
pp. 137-143 ◽  
Author(s):  
József TÖZSÉR ◽  
Péter BAGOSSI ◽  
Gábor ZAHUCZKY ◽  
Suzanne I. SPECHT ◽  
Eva MAJEROVA ◽  
...  
Keyword(s):  
Cleavage Site ◽  
Apoptotic Cell ◽  
Phosphorylation Site ◽  
Substantial Effect ◽  
Cellular Protein ◽  
Cleavage Sites ◽  
Potential Phosphorylation Site ◽  
Caspase Cleavage ◽  
Protein Substrates ◽  
Caspase Cleavage Site

Caspases are important mediators of apoptotic cell death. Several cellular protein substrates of caspases contain potential phosphorylation site(s) at the cleavage-site region, and some of these sites have been verified to be phosphorylated. Since phosphorylation may affect substantially the substrate susceptibility towards proteolysis, phosphorylated, non-phosphorylated and substituted oligopeptides representing such cleavage sites were studied as substrates of apoptotic caspases 3, 7 and 8. Peptides containing phosphorylated serine residues at P4 and P1′ positions were found to be substantially less susceptible towards proteolysis as compared with the serine-containing analogues, while phosphoserine at P3 did not have a substantial effect. P1 serine as well as P1-phosphorylated, serine-containing analogues of an oligopeptide representing the poly(ADP-ribose) polymerase cleavage site of caspase-3 were not hydrolysed by any of these enzymes, whereas the P1 aspartate-containing peptides were efficiently hydrolysed. These findings were interpreted with the aid of molecular modelling. Our results suggest that cleavage-site phosphorylation in certain positions could be disadvantageous or detrimental with respect to cleavability by caspases. Cleavage-site phosphorylation may therefore provide a regulatory mechanism to protect substrates from caspase-mediated degradation.

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