This essay has been submitted by a student. This is not an example of the work written by professional essay writers.

Cell Signalling and G-protein

downloadDownload printPrint

Pssst… we can write an original essay just for you.

Any subject. Any type of essay. We’ll even meet a 3-hour deadline.

Get your price

121 writers online

Download PDF

A cell’s ability to respond to its environment is essential to its survival. Short term-responses to environmental stimuli, which can occur rapidly and are usually reversible, most often result from modification of existing proteins. The long-term response, are usually the result of changes in the transcription of genes. Extracellular signals that induce long-term responses to affect many aspects of cell function; division, differentiation, and even communication with other cells. Alterations in these signaling pathways cause many human diseases including cancer, diabetes, and immune defects. In order to illustrate the variety of mechanisms used to activate key transcription factors, the eight classes of cell surface receptors and the intracellular signal pathways that they activate area important. Ligand binding to many receptors causes activation by inducing two or more receptor molecules to form a complex on the cell surface. Most signaling pathways involve one or more protein Kinases.

Many extracellular signaling molecules are synthesized and released by signaling cells within the organism. In all cases, signaling molecules produce a specific response only in target cells that have receptors for the signaling molecules. Many types of chemicals are used as signals: small molecules, peptides, soluble proteins, and many proteins presented to the surface of a cell or found to the extracellular matrix. Most receptors bind a signal molecule are a group of closely related molecules.

Most signaling molecules, however, are too large and too hydrophilic to penetrate through the plasma membrane. These bind to cell surface receptors that are integral proteins on the plasma membrane. Cell surface receptors generally consist of three discrete segments: a segment on the extracellular surface, a segment that spans the plasma membrane and a segment facing the cytosol. The signaling molecules act as a ligand which binds to a structurally complementary site on the extracellular or membrane-spanning domains of the receptors. Binding of the ligand induces a conformational change in the receptor that is transmitted through the membrane-spanning domain to the cytosolic Domain resulting in binding to and subsequent activation of other proteins in the cytosol or attached to the plasma membrane. The overall process of converting extracellular signals into intracellular responses as well as the individual steps in these processes is termed as Signal transduction. The molecules involved in the process is called Signal transducers.

Most ligands are responsible for cell-cell signaling (including neurotransmitters, peptide hormones, and growth factors) bind to receptors on the surface of their target cells. A major aspect in understanding the cell-cell signaling is understanding the mechanisms by which cell surface receptors transmit the signals initiated by ligand binding. Cell surface receptors, including the receptors for peptide hormones and growth factors, act instead by regulating the activity of intracellular proteins. These proteins then transmit signals from the receptor to a series of additional intracellular targets, frequently including transmission factors. Ligand binding to a receptor on the surface of the cell thus initiates a chain of intracellular reactions, ultimately reaching the target cell nucleus and resulting in programmed changes in Gene Expression.

G Protein-Coupled Receptors

The largest family of cell surface receptor transmits a signal to intracellular targets via the intermediary action of guanine nucleotides binding proteins called G proteins. Nearly thousand such G protein-coupled receptors have been identified including the receptors for Eicosanoids, many neurotransmitters, neuropeptides, and peptides hormones. In addition, the G-Protein coupled receptor family includes a large number of receptors that are responsible for smell, site, and taste

The G-Protein Coupled receptors are structurally and functionally related proteins characterized by seven membrane-spanning alpha helices. The binding of Ligands to the extracellular domains of these receptor induces a conformational change that allows the cytosolic domain of the receptors to activate a G-Protein associated with the inner phases of the plasma membrane. The activated G-protein then dissociates from the receptors and carries the signal to an intracellular target, which may be either an enzyme or an ion channels.

Remember: This is just a sample from a fellow student.

Your time is important. Let us write you an essay from scratch

experts 450+ experts on 30 subjects ready to help you just now

delivery Starting from 3 hours delivery

Find Free Essays

We provide you with original essay samples, perfect formatting and styling

Cite this Essay

To export a reference to this article please select a referencing style below:

Cell signalling and G-Protein. (2018, October 22). GradesFixer. Retrieved November 30, 2021, from
“Cell signalling and G-Protein.” GradesFixer, 22 Oct. 2018,
Cell signalling and G-Protein. [online]. Available at: <> [Accessed 30 Nov. 2021].
Cell signalling and G-Protein [Internet]. GradesFixer. 2018 Oct 22 [cited 2021 Nov 30]. Available from:
copy to clipboard

Sorry, copying is not allowed on our website. If you’d like this or any other sample, we’ll happily email it to you.

    By clicking “Send”, you agree to our Terms of service and Privacy statement. We will occasionally send you account related emails.


    Attention! This essay is not unique. You can get a 100% Plagiarism-FREE one in 30 sec

    Receive a 100% plagiarism-free essay on your email just for $4.99
    get unique paper
    *Public papers are open and may contain not unique content
    download public sample

    Sorry, we could not paraphrase this essay. Our professional writers can rewrite it and get you a unique paper.



    Please check your inbox.

    Want us to write one just for you? We can custom edit this essay into an original, 100% plagiarism free essay.

    thanks-icon Order now

    Hi there!

    Are you interested in getting a customized paper?

    Check it out!
    Having trouble finding the perfect essay? We’ve got you covered. Hire a writer

    Haven't found the right essay?

    Get an expert to write you the one you need!


    Professional writers and researchers


    Sources and citation are provided


    3 hour delivery