Proteinase-mediated cell signalling: targeting proteinase-activated receptors (PARs) by kallikreins and more

2006 ◽  
Vol 387 (6) ◽  
pp. 677-685 ◽  
Author(s):  
Katerina Oikonomopoulou ◽  
Kristina K. Hansen ◽  
Mahmoud Saifeddine ◽  
Nathalie Vergnolle ◽  
Illa Tea ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Physiological Responses ◽  
Cell Signalling ◽  
Target Cells ◽  
Serine Proteinases ◽  
Catalytic Domains ◽  
Proteinase Activated Receptors ◽  
G Protein Coupled ◽  
Unique Mechanism ◽  
Receptor Family

AbstractSerine proteinases, like trypsin, can play a hormone-like role by triggering signal transduction pathways in target cells. In many respects these hormone-like actions of proteinases can now be understood in terms of the pharmacodynamics of the G protein-coupled ‘receptor’ responsible for the cellular actions of thrombin (proteinase-activated receptor-1, or PAR1). PAR1, like the other three members of this receptor family (PAR2, PAR3and PAR4), has a unique mechanism of activation involving the proteolytic unmasking of an N-terminally tethered sequence that can activate the receptor. The selective activation of each PAR by short synthetic peptides representing these sequences has demonstrated that PAR1, PAR2and PAR4play important roles in regulating physiological responses ranging from vasoregulation and cell growth to inflammation and nociception. We hypothesise that the tissue kallikreins may regulate signal transduction via the PARs. Although PARs can account for many of their biological actions, kallikreins may also cause effects by mechanisms not involving the PARs. For instance, trypsin activates the insulin receptor and thrombin can act via a mechanism involving its non-catalytic domains. Based on the data we summarise, we propose that the kallikreins, like thrombin and trypsin, must now be considered as important ‘hormonal’ regulators of tissue function.

scholarly journals Prostatic trypsin-like kallikrein-related peptidases (KLKs) and other prostate-expressed tryptic proteinases as regulators of signalling via proteinase-activated receptors (PARs)

2008 ◽  
Vol 389 (6) ◽  
Author(s):  
Andrew J. Ramsay ◽  
Janet C. Reid ◽  
Mark N. Adams ◽  
Hemamali Samaratunga ◽  
Ying Dong ◽  
...  
Keyword(s):  
Serine Proteinase ◽  
Cellular Responses ◽  
Serine Proteinases ◽  
Inhibitory Mechanisms ◽  
Lysine Residues ◽  
Proteinase Activated Receptors ◽  
A Site ◽  
Potential Interactions ◽  
G Protein Coupled ◽  
Serine Proteinase Activity

AbstractThe prostate is a site of high expression of serine proteinases including members of the kallikrein-related peptidase (KLK) family, as well as other secreted and membrane-anchored serine proteinases. It has been known for some time that members of this enzyme family elicit cellular responses by acting directly on cells. More recently, it has been recognised that for serine proteinases with specificity for cleavage after arginine and lysine residues (trypsin-like or tryptic enzymes) these cellular responses are often mediated by cleavage of members of the proteinase-activated receptor (PAR) family – a four member sub-family of G protein-coupled receptors. Here, we review the expression of PARs in prostate, the ability of prostatic trypsin-like KLKs and other prostate-expressed tryptic enzymes to cleave PARs, as well as the prostate cancer-associated consequences of PAR activation. In addition, we explore the dysregulation of trypsin-like serine proteinase activity through the loss of normal inhibitory mechanisms and potential interactions between these dysregulated enzymes leading to aberrant PAR activation, intracellular signalling and cancer-promoting cellular changes.

scholarly journals Getting the message across: Pathophysiology and signaling via receptors for polypeptide hormones and proteinases

2010 ◽  
Vol 33 (2) ◽  
pp. 133 ◽  
Author(s):  
Morley D Hollenberg
Keyword(s):  
Drug Targets ◽  
Time Span ◽  
Activation Mechanism ◽  
Therapeutic Implications ◽  
Proteinase Activated Receptors ◽  
Tethered Ligand ◽  
Polypeptide Hormones ◽  
G Protein Coupled ◽  
Receptor Family

This article provides a personalized overview of the role of proteinases in generating hormone-like cell signals. Also outlined is the unexpected route of discovery that led one investigator over a four-decade time span, from early studies of the interactions of oxytocin and vasopressin with their neurophysin binding proteins to current studies of the tethered ligand activation mechanism that is unique for the G-protein-coupled family of proteinase-activated receptors (PARs). The focus is not only on the intriguing PAR receptor family, but also on alternative mechanisms whereby proteinases activate signal transduction pathways. Also summarized are the potential physiological and pathophysiological roles that PARs may play in the setting of inflammatory disorders ranging from arthritis to colitis. The therapeutic implications of considering PARs as drug targets are also discussed.

scholarly journals Mentors And The Butterfly Effect: Triggers For Discovering Signalling by Proteinases via Proteinase-Activated Receptors (PARs) And More

2012 ◽  
Vol 35 (6) ◽  
pp. 378
Author(s):  
Morley D Hollenberg
Keyword(s):  
Inflammatory Disease ◽  
Cell Function ◽  
Cell Signalling ◽  
The Novel ◽  
Molecular Pharmacology ◽  
Proteinase Activated Receptors ◽  
Butterfly Effect ◽  
The One ◽  
G Protein Coupled

The essential role of proteinases as regulatory digestive enzymes, recognized since the late 1800s, has been underscored by the discovery that more than 2% of the genome codes for proteinases and their inhibitors. Further, by the early 1970s it was appreciated that in addition to their digestive actions, proteinases can affect cell function: (1) by the generation or degradation of peptide hormones and (2) by the direct regulation of signalling by receptors like the one for insulin. It was the discovery in the 1990s of the novel G-protein-coupled ‘proteinase-activated receptor’ (PAR) family that has caused a paradigm shift in the understanding of the way that proteinases can regulate cell signalling. This overview provides a perspective for the discovery of the PARs and my laboratory’s role in (1) understanding the molecular pharmacology of these fascinating receptors and (2) identifying the potential pathophysiological roles that the PAR family can play in inflammatory disease. In this context, the overview also portrays the essential impact that seemingly minor comments/insights provided by my lifelong mentors have had on kindling my intense interest in proteinase-mediated signalling. The ‘butterfly effect’ of those comments has led to an unexpectedly large impact on my own research directions. Hopefully my own ‘butterfly comments’ will also be heard by my trainees and other colleagues with whom I am currently working and will promote future discoveries that will be directly relevant to the treatment of inflammatory disease.

scholarly journals Adhesion GPCRs in Glioblastoma

2021 ◽  
Author(s):  
Gabriele Stephan ◽  
Niklas Ravn-Boess ◽  
Dimitris G Placantonakis
Keyword(s):  
G Protein ◽  
G Protein Coupled Receptors ◽  
The Past ◽  
Novel Treatment ◽  
The Family ◽  
Health And Disease ◽  
Basic Biology ◽  
G Protein Coupled ◽  
Potential Use ◽  
Receptor Family

Abstract Members of the adhesion family of G protein-coupled receptors (GPCRs) have received attention for their roles in health and disease, including cancer. Over the past decade, several members of the family have been implicated in the pathogenesis of glioblastoma. Here, we discuss the basic biology of adhesion GPCRs and review in detail specific members of the receptor family with known functions in glioblastoma. Finally, we discuss the potential use of adhesion GPCRs as novel treatment targets in neuro-oncology.

scholarly journals Characterization of the G protein-coupled receptor family SREB across fish evolution

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Timothy S. Breton ◽  
William G. B. Sampson ◽  
Benjamin Clifford ◽  
Anyssa M. Phaneuf ◽  
Ilze Smidt ◽  
...  
Keyword(s):  
G Protein ◽  
Genomic Structure ◽  
Integrated Approach ◽  
Orphan Receptor ◽  
Specific Gene ◽  
Testicular Development ◽  
Brain Expression ◽  
And Function ◽  
G Protein Coupled ◽  
Receptor Family

AbstractThe SREB (Super-conserved Receptors Expressed in Brain) family of G protein-coupled receptors is highly conserved across vertebrates and consists of three members: SREB1 (orphan receptor GPR27), SREB2 (GPR85), and SREB3 (GPR173). Ligands for these receptors are largely unknown or only recently identified, and functions for all three are still beginning to be understood, including roles in glucose homeostasis, neurogenesis, and hypothalamic control of reproduction. In addition to the brain, all three are expressed in gonads, but relatively few studies have focused on this, especially in non-mammalian models or in an integrated approach across the entire receptor family. The purpose of this study was to more fully characterize sreb genes in fish, using comparative genomics and gonadal expression analyses in five diverse ray-finned (Actinopterygii) species across evolution. Several unique characteristics were identified in fish, including: (1) a novel, fourth euteleost-specific gene (sreb3b or gpr173b) that likely emerged from a copy of sreb3 in a separate event after the teleost whole genome duplication, (2) sreb3a gene loss in Order Cyprinodontiformes, and (3) expression differences between a gar species and teleosts. Overall, gonadal patterns suggested an important role for all sreb genes in teleost testicular development, while gar were characterized by greater ovarian expression that may reflect similar roles to mammals. The novel sreb3b gene was also characterized by several unique features, including divergent but highly conserved amino acid positions, and elevated brain expression in puffer (Dichotomyctere nigroviridis) that more closely matched sreb2, not sreb3a. These results demonstrate that SREBs may differ among vertebrates in genomic structure and function, and more research is needed to better understand these roles in fish.

scholarly journals Nonameric Peptide Orchestrates Signal Transduction in the Activating HLA-E/NKG2C/CD94 Immune Complex as Revealed by All-Atom Simulations

2021 ◽  
Vol 22 (13) ◽  
pp. 6670
Author(s):  
Eva Prašnikar ◽  
Andrej Perdih ◽  
Jure Borišek
Keyword(s):  
Signal Transduction ◽  
Cell Activation ◽  
Nk Cell ◽  
Innate Immune ◽  
Target Cells ◽  
Molecular Events ◽  
Activating Receptors ◽  
Molecular Machinery ◽  
Infected Cells ◽  
Bond Network

The innate immune system’s natural killer (NK) cells exert their cytolytic function against a variety of pathological challenges, including tumors and virally infected cells. Their activation depends on net signaling mediated via inhibitory and activating receptors that interact with specific ligands displayed on the surfaces of target cells. The CD94/NKG2C heterodimer is one of the NK activating receptors and performs its function by interacting with the trimeric ligand comprised of the HLA-E/β2m/nonameric peptide complex. Here, simulations of the all-atom multi-microsecond molecular dynamics in five immune complexes provide atomistic insights into the receptor–ligand molecular recognition, as well as the molecular events that facilitate the NK cell activation. We identify NKG2C, the HLA-Eα2 domain, and the nonameric peptide as the key elements involved in the molecular machinery of signal transduction via an intertwined hydrogen bond network. Overall, the study addresses the complex intricacies that are necessary to understand the mechanisms of the innate immune system.

scholarly journals Every Detail Matters. That Is, How the Interaction between Gα Proteins and Membrane Affects Their Function

Membranes ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 222
Author(s):  
Agnieszka Polit ◽  
Paweł Mystek ◽  
Ewa Błasiak
Keyword(s):  
Signal Transduction ◽  
G Protein ◽  
G Proteins ◽  
Lipid Membranes ◽  
Signaling Proteins ◽  
Heterotrimeric G Proteins ◽  
Membrane Attachment ◽  
The Individual ◽  
Multicellular Organisms ◽  
G Protein Coupled

In highly organized multicellular organisms such as humans, the functions of an individual cell are dependent on signal transduction through G protein-coupled receptors (GPCRs) and subsequently heterotrimeric G proteins. As most of the elements belonging to the signal transduction system are bound to lipid membranes, researchers are showing increasing interest in studying the accompanying protein–lipid interactions, which have been demonstrated to not only provide the environment but also regulate proper and efficient signal transduction. The mode of interaction between the cell membrane and G proteins is well known. Despite this, the recognition mechanisms at the molecular level and how the individual G protein-membrane attachment signals are interrelated in the process of the complex control of membrane targeting of G proteins remain unelucidated. This review focuses on the mechanisms by which mammalian Gα subunits of G proteins interact with lipids and the factors responsible for the specificity of membrane association. We summarize recent data on how these signaling proteins are precisely targeted to a specific site in the membrane region by introducing well-defined modifications as well as through the presence of polybasic regions within these proteins and interactions with other components of the heterocomplex.

scholarly journals Development and Interrogation of a Transcriptomic Resource for the Giant Triton Snail (Charonia tritonis)

2021 ◽  
Author(s):  
AH Klein ◽  
CA Motti ◽  
AK Hillberg ◽  
T Ventura ◽  
P Thomas-Hall ◽  
...  
Keyword(s):  
Developmental Stages ◽  
Cell Signalling ◽  
Natural Populations ◽  
Olfactory Receptors ◽  
Gill Tissue ◽  
Abundant Species ◽  
Population Outbreaks ◽  
Coral Reef Ecosystems ◽  
Specialist Predators ◽  
G Protein Coupled

AbstractGastropod molluscs are among the most abundant species that inhabit coral reef ecosystems. Many are specialist predators, along with the giant triton snail Charonia tritonis (Linnaeus, 1758) whose diet consists of Acanthaster planci (crown-of-thorns starfish), a corallivore known to consume enormous quantities of reef-building coral. C. tritonis are considered vulnerable due to overexploitation, and a decline in their populations is believed to have contributed to recurring A. planci population outbreaks. Aquaculture is considered one approach that could help restore natural populations of C. tritonis and mitigate coral loss; however, numerous questions remain unanswered regarding their life cycle, including the molecular factors that regulate their reproduction and development. In this study, we have established a reference C. tritonis transcriptome derived from developmental stages (embryo and veliger) and adult tissues. This was used to identify genes associated with cell signalling, such as neuropeptides and G protein-coupled receptors (GPCRs), involved in endocrine and olfactory signalling. A comparison of developmental stages showed that several neuropeptide precursors are exclusively expressed in post-hatch veligers and functional analysis found that FFamide stimulated a significant (20.3%) increase in larval heart rate. GPCRs unique to veligers, and a diversity of rhodopsin-like GPCRs located within adult cephalic tentacles, all represent candidate olfactory receptors. In addition, the cytochrome P450 superfamily, which participates in the biosynthesis and degradation of steroid hormones and lipids, was also found to be expanded with at least 91 genes annotated, mostly in gill tissue. These findings further progress our understanding of C. tritonis with possible application in developing aquaculture methods.

scholarly journals The apelin receptor: physiology, pathology, cell signalling, and ligand modulation of a peptide-activated class A GPCR

2014 ◽  
Vol 92 (6) ◽  
pp. 431-440 ◽  
Author(s):  
Nigel A. Chapman ◽  
Denis J. Dupré ◽  
Jan K. Rainey
Keyword(s):  
G Protein ◽  
Cell Signalling ◽  
Wide Distribution ◽  
Peptide Ligand ◽  
Cellular Effects ◽  
Class A ◽  
Promising Therapeutic Target ◽  
Apelin Receptor ◽  
Obesity And Cancer ◽  
G Protein Coupled

The apelin receptor (AR or APJ) is a class A (rhodopsin-like) G-protein-coupled receptor with wide distribution throughout the human body. Activation of the AR by its cognate peptide ligand, apelin, induces diverse physiological effects including vasoconstriction and dilation, strengthening of heart muscle contractility, angiogenesis, and regulation of energy metabolism and fluid homeostasis. Recently, another endogenous peptidic activator of the AR, Toddler/ELABELA, was identified as having a crucial role in zebrafish (Danio rerio) embryonic development. The AR is also implicated in pathologies including cardiovascular disease, diabetes, obesity, and cancer, making it a promising therapeutic target. Despite its established importance, the precise roles of AR signalling remain poorly understood. Moreover, little is known about the mechanisms of peptide–AR activation. Additional complexity arises from modulation of the AR by 2 endogenous peptide ligands, both with multiple bioactive isoforms of variable length and distribution. The various apelin and Toddler/ELABELA isoforms may also produce distinct cellular effects. Further complexity arises through formation of functionally distinct heterodimers between the AR and other G-protein-coupled receptors. This minireview outlines key (patho)physiological actions of the AR, addresses what is known about signal transduction downstream of AR activation, and concludes by discussing unique properties of the endogenous peptidic ligands of the AR.

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