scholarly journals Tooth enamel protein amelogenin binds to ameloblast cell membrane-mimicking vesicles via its N-terminus

2015 ◽  
Vol 464 (3) ◽  
pp. 956-961 ◽  
Author(s):  
Sowmya Bekshe Lokappa ◽  
Karthik Balakrishna Chandrababu ◽  
Janet Moradian-Oldak
Keyword(s):  
Cell Membrane ◽  
Tooth Enamel ◽  
N Terminus ◽  
Enamel Protein

Relative Levels of mRNA Encoding Enamel Proteins in Enamel Organ Epithelia and Odontoblasts

2003 ◽  
Vol 82 (12) ◽  
pp. 982-986 ◽  
Author(s):  
T. Nagano ◽  
S. Oida ◽  
H. Ando ◽  
K. Gomi ◽  
T. Arai ◽  
...  
Keyword(s):  
Tooth Enamel ◽  
Structural Proteins ◽  
Enamel Organ ◽  
Maturation Stage ◽  
Mrna Levels ◽  
Rt Pcr ◽  
Enamel Protein ◽  
Enamel Proteins ◽  
Enamel Layer

Amelogenin, enamelin, sheathlin (ameloblastin/ amelin), enamelysin (MMP-20), and KLK4 (EMSP-1) are the major structural proteins and proteinases in developing tooth enamel. Recently, odontoblasts were reported to express amelogenin, the most abundant enamel protein. In this study, we hypothesized that odontoblasts express all enamel proteins and proteases, and we measured their relative mRNA levels in enamel organ epithelia and odontoblasts associated with porcine secretory- and maturation-stage enamel by RT-PCR, using a LightCycler instrument. The results showed that amelogenin mRNA in secretory-stage EOE is 320-fold higher than in odontoblasts beneath secretory-stage enamel, and over 20,000-fold higher than in odontoblasts under maturation-stage enamel. Similar results were obtained for enamelin and sheathlin. Enamelysin mRNA levels were equivalent in these two tissues, while KLK4 mRNA was higher in odontoblasts than in secretory-stage EOE. These results support the conclusion that odontoblasts are involved in the formation of the enamel layer adjacent to enamel-dentin junction.

scholarly journals Structural adaptation of tooth enamel protein amelogenin in the presence of SDS micelles

Biopolymers ◽  
2014 ◽  
Vol 101 (5) ◽  
pp. 525-535 ◽  
Author(s):  
Karthik Balakrishna Chandrababu ◽  
Kaushik Dutta ◽  
Sowmya Bekshe Lokappa ◽  
Moise Ndao ◽  
John Spencer Evans ◽  
...  
Keyword(s):  
Tooth Enamel ◽  
Structural Adaptation ◽  
Sds Micelles ◽  
Enamel Protein

scholarly journals Membrane orientation of Rh(D) polypeptide and partial localization of its epitope-containing domain

Blood ◽  
1992 ◽  
Vol 79 (3) ◽  
pp. 808-812 ◽  
Author(s):  
K Suyama ◽  
J Goldstein
Keyword(s):  
Cell Membrane ◽  
Antibody Preparation ◽  
Terminal Domain ◽  
C Terminus ◽  
N Terminus ◽  
D Cells ◽  
Related Proteins ◽  
Cytoplasmic Side ◽  
Antigenic Domain

Abstract We have previously shown that the effects of various enzyme treatments on Rh antigen-containing polypeptides in situ could be monitored by an antibody preparation which recognizes only these polypeptides following Western blotting. We now have prepared antibodies that specifically react with either the N- or C-terminal ends of Rh-related proteins. Using all three, we have established that the C-terminus of Rh(D) polypeptide is at the cell surface, whereas its N-terminal domain is situated at the cytoplasmic side of the red blood cell membrane. Chymotrypsin digestion of ghosts derived from (-D-/-D-) cells that are devoid of Rh (C/c) and (E/e) antigens produces three major Rh(D)- related fragments: the 20-Kd fragment contains the molecule's C- terminal domain, the 17-Kd fragment its N-terminus, and the 13-Kd fragment neither. However, only the 17-Kd fragment forms an immune- complex with human polyclonal anti-D, indicating that it contains the Rh(D) antigenic domain. Other findings presented here provide further evidence for a unique folding of Rh(D) polypeptide within the cell membrane and suggest that Rh(C/c) and (E/e) polypeptides, when present, may form complexes with it.

scholarly journals Membrane orientation of Rh(D) polypeptide and partial localization of its epitope-containing domain

Blood ◽  
1992 ◽  
Vol 79 (3) ◽  
pp. 808-812
Author(s):  
K Suyama ◽  
J Goldstein
Keyword(s):  
Cell Membrane ◽  
Antibody Preparation ◽  
Terminal Domain ◽  
C Terminus ◽  
N Terminus ◽  
D Cells ◽  
Related Proteins ◽  
Cytoplasmic Side ◽  
Antigenic Domain

We have previously shown that the effects of various enzyme treatments on Rh antigen-containing polypeptides in situ could be monitored by an antibody preparation which recognizes only these polypeptides following Western blotting. We now have prepared antibodies that specifically react with either the N- or C-terminal ends of Rh-related proteins. Using all three, we have established that the C-terminus of Rh(D) polypeptide is at the cell surface, whereas its N-terminal domain is situated at the cytoplasmic side of the red blood cell membrane. Chymotrypsin digestion of ghosts derived from (-D-/-D-) cells that are devoid of Rh (C/c) and (E/e) antigens produces three major Rh(D)- related fragments: the 20-Kd fragment contains the molecule's C- terminal domain, the 17-Kd fragment its N-terminus, and the 13-Kd fragment neither. However, only the 17-Kd fragment forms an immune- complex with human polyclonal anti-D, indicating that it contains the Rh(D) antigenic domain. Other findings presented here provide further evidence for a unique folding of Rh(D) polypeptide within the cell membrane and suggest that Rh(C/c) and (E/e) polypeptides, when present, may form complexes with it.

scholarly journals Constitutive recycling of the store-operated Ca2+ channel Orai1 and its internalization during meiosis

2010 ◽  
Vol 191 (3) ◽  
pp. 523-535 ◽  
Author(s):  
Fang Yu ◽  
Lu Sun ◽  
Khaled Machaca
Keyword(s):  
Steady State ◽  
Cell Membrane ◽  
Subcellular Localization ◽  
Oocyte Maturation ◽  
Vesicular Trafficking ◽  
Endocytic Pathway ◽  
Consensus Binding Site ◽  
Significant Percentage ◽  
Store Depletion ◽  
N Terminus

The egg’s competency to activate at fertilization and transition to embryogenesis is dependent on its ability to generate a fertilization-specific Ca2+ transient. To endow the egg with this capacity, Ca2+ signals remodel during oocyte maturation, including inactivation of the primary Ca2+ influx pathway store-operated Ca2+ entry (SOCE). SOCE inactivation is coupled to internalization of the SOCE channel, Orai1. In this study, we show that Orai1 internalizes during meiosis through a caveolin (Cav)- and dynamin-dependent endocytic pathway. Cav binds to Orai1, and we map a Cav consensus–binding site in the Orai1 N terminus, which is required for Orai1 internalization. Furthermore, at rest, Orai1 actively recycles between an endosomal compartment and the cell membrane through a Rho-dependent endocytic pathway. A significant percentage of total Orai1 is intracellular at steady state. Store depletion completely shifts endosomal Orai1 to the cell membrane. These results define vesicular trafficking mechanisms in the oocyte that control Orai1 subcellular localization at steady state, during meiosis, and after store depletion.

Evolution of Gram+ Streptococcus pyogenes has maximized efficiency of the Sortase A cleavage site

2021 ◽  
Author(s):  
Bradley M Readnour ◽  
Yetunde A Ayinuola ◽  
Brady Russo ◽  
Zhong Liang ◽  
Vincent A Fischetti ◽  
...  
Keyword(s):  
Cell Membrane ◽  
Streptococcus Pyogenes ◽  
Cleavage Site ◽  
Transmembrane Domain ◽  
Sortase A ◽  
Double Mutation ◽  
Extracellular Milieu ◽  
N Terminus ◽  
Human Plasminogen

Human plasminogen (hPg)-binding M-protein (PAM), a major virulence factor of Pattern D Streptococcus pyogenes (GAS), is the primary receptor responsible for binding and activating hPg. PAM is covalently bound to the cell wall (CW) through cell membrane (CM)-resident sortase A (SrtA)-catalyzed cleavage of the PAM-proximal C-terminal LPST¯-GEAA motif present immediately upstream of its transmembrane domain (TMD), and subsequent transpeptidation to the CW. These steps expose the N-terminus of PAM to the extracellular milieu (EM) to interact with PAM ligands, e.g., hPg. Previously, we found that inactivation of SrtA showed little reduction in functional binding of PAM to hPg, indicating that PAM retained in the cell membrane (CM) by the TMD nonetheless exposed its N-terminus to the EM. In the current study, we assessed the effects of mutating the Thr4 (P1) residue of the SrtA-cleavage site in PAM (Thr355 in PAM) to delay PAM in the CM in the presence of SrtA. Using rSrtA in vitro, LPSYGEAA and LPSWGEAA peptides were shown to have low activities, while LPSTGEAA had the highest activity. Isolated CM fractions of AP53/DSrtA cells showed that LPSYGEAA and LPSWGEAA peptides were cleaved at substantially faster rates than LPSTGEAA, even in CMs with an AP53/DSrtA/PAM[T355Y] double mutation, but the transpeptidation step did not occur. These results implicate another CM-resident enzyme that cleaves LPSYGEAA and LPSWGEAA motifs, most likely LPXTGase, but cannot catalyze the transpeptidation step. We conclude that the natural P1 (Thr) of the SrtA cleavage site has evolved to dampen PAM from nonfunctional cleavage by LPXTGase.

scholarly journals Structural insights on melanocortin 5 receptor targeting to cell surface

2009 ◽  
Vol 15 (S3) ◽  
pp. 3-4 ◽  
Author(s):  
A. R. Rodrigues ◽  
H. Almeida ◽  
A. M. Gouveia
Keyword(s):  
Cell Membrane ◽  
Cell Surface ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
Melanocortin Receptors ◽  
N Terminus ◽  
Available Information ◽  
G Protein Coupled ◽  
Structural Insights ◽  
Human Receptor

AbstractThe melanocortin 5 receptor (MC5R) is a G-protein coupled receptor (GPCR) with a typical seventransmembrane-domain structure. It is assumed that all GPCRs undergo several post-transcriptional modifications during synthesis and folding until finally target to the cell membrane. The available information about the specific domains responsible for the correct targeting of the melanocortin receptors to the cell surface is scarce. Regarding MC5R, it was shown that the first 20 aminoacids of the human receptor can be deleted without affecting the ligand binding affinity, but further deletions of the N terminus resulted in total loss of binding. These results were not directly correlated with the cell surface expression levels of the receptor. Thus, we aim to define the specific MC5R domains important to its correct trafficking and signaling, and preliminary results are here presented.

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