Cellular Response

6 Key excerpts on "Cellular Response"

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  Cell Signaling

  • Wendell A. Lim, Wendell Lim, Bruce Mayer, Tony Pawson(Authors)
  • 2014(Publication Date)
  • Garland Science

    (Publisher)

  It is this interface between the unique proper-ties of living systems and the more universal properties of any system that processes information that makes the study of cellular signaling mechanisms so compelling. Introduction to Cell Signaling 1 2 Chapter 1 Introduction to Cell Signaling All cells have the ability to respond to their environment While biologists and philosophers may not all agree on the precise defini-tion of life, most definitions include a number of common properties, such as autonomy, the ability to generate energy, and the ability to reproduce. One of these common properties is adaptability—the ability to respond to changes in the environment. We all understand that one way to test whether a thing is animate or inanimate, or living or dead, is to poke it and see if it responds. Single-celled organisms display the ability to detect diverse molecular species and stresses in their environment, and are able to change aspects of their gene expression, growth, structure, and metabolism in response, usually to improve their ability to survive under changing conditions. With the emergence of multicellular organisms, individual cells within the organism evolved the highly specialized ability to sense specific sig-nals transmitted from other cells in the organism, allowing for extraor-dinary levels of communication within the organism. The coordinated regulation of growth, death, morphology, and metabolism is absolutely essential for many individual cells to function in concert as an integrated organism. Moreover, cells have the ability to monitor aspects of their own internal state, and to respond in a self-correcting way—the foundation of cellular homeostasis and repair. Thus, cell signaling, which encompasses the study of this wide range of stimulus–response behaviors observed in cells, is central to all of biology.

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  Disease Pathways

  An Atlas of Human Disease Signaling Pathways

  • Anastasia P. Nesterova, Anton Yuryev, Eugene A. Klimov, Maria Zharkova, Maria Shkrob, Natalia V. Ivanikova, Sergey Sozin, Vladimir Sobolev(Authors)
  • 2019(Publication Date)
  • Elsevier

    (Publisher)

  Biological process —a series of events with a defined beginning and end, which affects essential functions of the live organism. (Examples are nerve transmission, gastric acid release, and brain development.)

  Cell process —a biological process that describes events on the cellular level that changes the cell’s behavior and functions. (Examples are apoptosis, chemotaxis, and phagocytosis.)

  Network —a database of interactions between molecules or/and biological processes without clear logic and causal relationships.

  Introduction to cell signaling

  All living organisms share the ability to respond to external stimuli. Cells in a multicellular organism can change their status in response to various biochemical and electrochemical impulses, and they can communicate with each other using short- and long-distance signals. The ability to receive and transmit signals is vital for survival both at the cellular and the whole organism level. Cell signaling includes three major stages: signal perception (receiving of a signal), signal transduction (composed of a series of intracellular biochemical reactions), and Cellular Response.

  Signal reception

  Various signals stimulate the cell—molecular, electrochemical, and mechanical, or physical signals all affect and elicit a Cellular Response. The most common means of cellular activation is via specific proteins on the cell surface or within the cell that can sense stimulatory biomolecules. Those molecules that react to stimulatory biomolecules are termed receptors. Signaling molecules that bind receptors—termed ligands —can be proteins, peptides, or other molecules. Ligand binding causes a conformational change in the receptor and transmission of the signal to other cellular proteins, which may or may not be bound to the receptor. Intercellular interactions are also conducted through various receptor-mediated signals. For instance, the regulation of interactions between neighboring cells can involve transmembrane notch receptors that are activated by the jagged (JAG1,2) or delta (DLL) ligands to trigger evolutionarily conserved signaling pathways important for the development of tissues and organs (Favarolo and López, 2018 ; Polychronidou et al., 2015

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  Mechanotransduction

  Cell Signaling to Cell Response

  • Paul A. Sundaram, Paul Sundaram(Authors)
  • 2020(Publication Date)
  • Academic Press

    (Publisher)

  The purpose of a signal in a cell is to accomplish some type of physiological function. Hence, the cell has to receive a signal, which then results in transduction within the cell and ultimately causes the cell to perform its function. In a nutshell, the overall mechanism in cell communication, including the initiation and response to a signal, consists of three distinct phases or steps: (1) signal reception, (2) signal transduction, and (3) signal response. The cell receives a signal through ligand binding with a receptor protein, which has both an extracellular portion to capture the signal and an intracellular or cytosol part, which transmits the signal to other intracellular proteins in a process called transduction. The signal is finally received by effector proteins, which accomplish the physiological function of the cell as the response. In what follows, a bird’s-eye view of the cell signaling process is provided without attempting to get into details of advanced biochemical reactions that occur in these processes, which are beyond the scope of this book. However, sufficient information is provided for the reader to grasp the fundamentals of cell signaling. Advanced students are directed to study this phenomenon in many research articles that are available, which deal specifically with this topic.

  2.2 Modes of cell communication

  Cell signaling entails the transmission of information from one cell to another cell or a group of cells. Hence, cells must be able to communicate with each other to pass along this information onward. Faulty communication between cells results in deficiency in the transmission of information, which, in the human body, may lead to pathologies or disease. In a complex multicellular system such as the human body, it is imperative that there is effective communication between different cell groups for proper functioning of the system. It should be noted that there is a redundancy in the signaling, resulting in the same cell function, in case the primary signal is unable to accomplish its objective because of a deficiency in that signaling pathway. There is a plethora of communication pathways between cells and groups of cells. Cells respond to a variety of signals, which can be classified as chemical and mechanical stimuli. In a general sense, all cells are subjected to some kind of signaling, which elicits a physiological response. If we think about a simple sensation such as hunger, the initial signal comes from the pituitary gland, which in and of itself is triggered by a lack of energy production in the body. This signal is followed by the secretion of gastric juices in the stomach, which causes a “burning” sensation, creating an urge in us to consume food. The feedback from the energy generated by the breakdown of sugars from the food that was ingested results in the signal being shut off until more energy is needed.

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  Human Physiology

  • Bryan H. Derrickson(Author)
  • 2019(Publication Date)
  • Wiley

    (Publisher)

  Examples of Cellular Responses include the trans- port of a substance across the plasma membrane, the synthe- sis of a new molecule, a change in the rate of a specific metabolic reaction, or contraction if the cell is a muscle cell. The process by which a signal molecule (the messenger) is transduced (converted) into a Cellular Response is referred to as signal transduction. During signal transduction, there is a specific sequence of events that occurs between the binding of the extracellular messenger to the receptor and the Cellular Response (Figure 6.12). This sequence of events, referred to as a signal transduction pathway, or signaling pathway, involves actions that cause a change in a key protein of the cell. This protein, known as an effector protein, in turn causes the Cellular Response (Figure 6.12). For example, the effector protein may be a contractile protein that causes contraction, an ion channel that permits movement of certain ions across the plasma membrane, or an enzyme that promotes a specific metabolic reaction. In many signal transduction pathways, a series of relay proteins conveys the signal between the recep- tor and the effector protein. When this occurs, each relay pro- tein causes a change in the next protein in line until there is a change in the effector protein. Signal transduction pathways can differ in the number of relay proteins that they contain. Relay proteins and the effector protein may be present in the plasma membrane or cytosol of the target cell. Extracellular chemical messengers vary in the types of signal transduction pathways that they activate. Some mes- sengers activate completely different signal transduction pathways in their target cells, with each pathway containing a unique set of relay proteins and effector proteins. Other messengers, however, activate similar signal transduction pathways in their target cells, differing mainly in the effector protein that is altered in the last step of the pathway.

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  The Evolution of Intelligent Systems

  How Molecules became Minds

  • K. Richardson(Author)
  • 2010(Publication Date)
  • Palgrave Macmillan

    (Publisher)

  The cell does not, now, exist independently, but in a changing profusion of signals from other cells, collectively deal- ing with another profusion of signals from the changing outside world. It is hardly surprising, therefore, that all activity within cells is acutely dependent upon signals from other cells. Without those Bodily Intelligence 57 signals all cell activity stops, as if, like a rabbit in car headlights, frozen by confusion. Signaling in complex environments The immediate environment of any individual cell is the extracellular matrix and fluids. It is not by any means an empty space, but contains a throng of factors and signals from other cells and tissues. Nor will these be randomly or evenly distributed: rather they will tend to have some underlying pattern or structure. As with bacteria, sensitivity to this pat- tern is mediated through cell membranes by means of specialised recep- tors. A ligand, or signaling protein, in the extracellular fluid, produced from some other cell far or near, binds to a specific receptor. The receptor then undergoes shape transformation, which, in turn, initiates (or can inhibit) responses within. 1 This is by no means a routine process, though. The traditional view of cells passively receiving independent environ- mental cues to which they respond in isolation from other cues is now being transcended. 2 At any one time the cell surface is being bombarded by multiple inputs simultaneously. Dealing with these as if they were independent cues would only result in utter disorder. Instead, organised reponse requires continuous and precise integration of their ‘messages’. 3 Internal signaling assimilates external structure This context sensitivity of all cell activities is reflected in extensive internal signaling networks. Generally, binding of a ligand to its recep- tor activates biochemical pathways, including some leading to gene transcription, by triggering cascades of other signals.

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  Biology for AP® Courses

  • Julianne Zedalis, John Eggebrecht(Authors)
  • 2018(Publication Date)
  • Openstax

    (Publisher)

  382 Chapter 9 | Cell Communication This OpenStax book is available for free at http://cnx.org/content/col12078/1.6 Science Practice 6.1 The student can justify claims with evidence. Learning Objective 3.37 The student is able to justify claims based on scientific evidence that changes in signal transduction pathways can alter Cellular Response. Essential Knowledge 3.D.4 Changes in signal transduction pathways can alter Cellular Response. Science Practice 6.2 The student can construct explanations of phenomena based on evidence produced through scientific practices. Learning Objective 3.39 The student is able to construct an explanation of how certain drugs affect signal reception and, consequently, signal transduction pathways. Big Idea 2 Biological systems utilize free energy and molecular building blocks to grow, to reproduce, and to maintain dynamic homeostasis. Enduring Understanding 2.E Many biological processes involved in growth, reproduction and dynamic homeostasis include temporal regulation and coordination. Essential Knowledge 2.E.1 Timing and coordination of specific events are necessary for the normal development of an organism, and these events are regulated by a variety of mechanisms. Science Practice 7.1 The student can connect phenomena and models across spatial and temporal scales. Learning Objective 2.34 The student is able to describe the role of programmed cell death in development and differentiation, the reuse of molecules, and the maintenance of dynamic homeostasis. The Science Practice Challenge Questions contain additional test questions for this section that will help you prepare for the AP exam. These questions address the following standards: [APLO 3.33][APLO 3.35] Inside the cell, ligands bind to their internal receptors, allowing them to directly affect the cell’s DNA and protein-producing machinery. Using signal transduction pathways, receptors in the plasma membrane produce a variety of effects on the cell.

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