Immunohistochemical localization of prolactin receptor in human digestive tissues

Author(s):  
T. García-Caballero ◽  
R. Gallego ◽  
M. Fraga ◽  
E. Pintos ◽  
A. Beiras

Prolactin (PRL) is primarily recognized for its lactogenic effect. However, it is known that this polypeptide hormone exerts a great variety of biological functions acting on reproduction, osmoregulation, growth, metabolism, immunomodulation and even on behavior. The actions of PRL initiate with hormone binding to a specific cell surface receptor that belongs to the cytokine/GH/PRL receptor family or the hematopoietin receptor family The PRLR is widely distributed in numerous tissues. The aim of the present work was to investigate by immunohistochemistry the cellular distribution of PRLR in the human gastrointestinal tract and associated glands (liver and pancreas).Samples of normal esophagus, stomach, small and large intestine, liver and pancreas were obtained from surgical pieces or recent autopsies. These samples were immersion-fixed in 10% buffered formalin for 24 hr, dehydrated and embedded in paraffin routinely. B6.2 anti-PRLR and avidin-biotin-peroxidase complex (ABC) procedure were employed. The B6.2 mouse monoclonal antibody (prepared against a membrane enriched fraction of human metastatic breast cancer), was generously provided by Dr. Barbara K. Vonderhaar and used at a dilution of 1:250, for 1 hr.

1986 ◽  
Vol 239 (3) ◽  
pp. 777-780 ◽  
Author(s):  
C Y Yang ◽  
F S Lee ◽  
L Chan ◽  
D A Sparrow ◽  
J T Sparrow ◽  
...  

Apolipoprotein B-100 (apo B-100) is the protein ligand in low-density lipoproteins that binds to a specific cell-surface receptor. Its molecular mass has been a subject of controversy. We have determined the molecular mass of the protein by a chemical approach. After complete CNBr cleavage, the C-terminal fragment of apo B-100 was purified by reverse-phase h.p.l.c. Amino acid N- and C-terminal analyses confirm that this peptide represents the C-terminal peptide as deduced from the DNA sequence of a human apo B-100 cDNA clone. A chemically synthesized peptide was used to determine the recovery of the peptide (74.72%). On the basis of these data, the molecular mass of apo B-100 was determined to be 496.82 +/- 24.84 kDa.


1987 ◽  
Vol 66 (1_suppl) ◽  
pp. 628-632 ◽  
Author(s):  
B. J. Baum

It is very well established that the principal control of salivary secretion is derived from autonomic innervation. Transmission of a neural signal to a salivary gland acinar cell occurs chemically via neurotransmitters, the first messengers of a secretory response. Neurotransmitters bind to specific cell surface receptor proteins, an event which activates precise transduction mechanisms which then transfer the neural signal to the inside of the cell. There are two major transduction mechanisms operative in salivary gland acinar cells. One involves the generation of cAMP, the other involves the breakdown of plasma membrane polyphosphoinositides. For both mechanisms, the appropriate stimulated receptor activates a second plasma membrane protein, termed an N (or G) protein. The N protein requires GTP to activate an enzyme (adenylate cyclase or phospholipase C), which then catalyzes the formation of a second messenger (cAMP and inositol trisphosphatel diacylglyeerol, respectively). This action provides the intracellular signal for secretory events (protein, fluid, electrolyte secretion) to begin.


2020 ◽  
Vol 21 (2) ◽  
pp. 636 ◽  
Author(s):  
Marta Spodzieja ◽  
Katarzyna Kuncewicz ◽  
Adam Sieradzan ◽  
Agnieszka Karczyńska ◽  
Justyna Iwaszkiewicz ◽  
...  

Immune checkpoints are crucial in the maintenance of antitumor immune responses. The activation or blockade of immune checkpoints is dependent on the interactions between receptors and ligands; such interactions can provide inhibitory or stimulatory signals, including the enhancement or suppression of T-cell proliferation, differentiation, and/or cytokine secretion. B-and T-lymphocyte attenuator (BTLA) is a lymphoid-specific cell surface receptor which is present on T-cells and interacts with herpes virus entry mediator (HVEM), which is present on tumor cells. The binding of HVEM to BTLA triggers an inhibitory signal which attenuates the immune response. This feature is interesting for studying the molecular interactions between HVEM and BTLA, as they may be targeted for novel immunotherapies. This work was based on the crystal structure of the BTLA/HVEM complex showing that BTLA binds the N-terminal cysteine-rich domain of HVEM. We investigated the amino acid sequence of HVEM and used molecular modeling methods to develop inhibitors of the BTLA/HVEM interaction. We synthesized novel compounds and determined their ability to interact with the BTLA protein and inhibit the formation of the BTLA/HVEM complex. Our results suggest that the HVEM (14–39) peptide is a potent inhibitor of the formation of the BTLA/HVEM protein complex.


1987 ◽  
Vol 66 (2_suppl) ◽  
pp. 628-632 ◽  
Author(s):  
B. J. Baum

It is very well established that the principal control of salivary secretion is derived from autonomic innervation. Transmission of a neural signal to a salivary gland acinar cell occurs chemically via neurotransmitters, the first messengers of a secretory response. Neurotransmitters bind to specific cell surface receptor proteins, an event which activates precise transduction mechanisms which then transfer the neural signal to the inside of the cell. There are two major transduction mechanisms operative in salivary gland acinar cells. One involves the generation of cAMP, the other involves the breakdown of plasma membrane polyphosphoinositides. For both mechanisms, the appropriate stimulated receptor activates a second plasma membrane protein, termed an N (or G) protein. The N protein requires GTP to activate an enzyme (adenylate cyclase or phospholipase C), which then catalyzes the formation of a second messenger (cAMP and inositol trisphosphate/diacylglycerol, respectively). This action provides the intracellular signal for secretory events (protein, fluid, electrolyte secretion) to begin.


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