Intercellular Communication

Written on June 6, 2009 No Comment

Cell-to-cell Communication (Cell Signaling)

“Almost without exception, whenever two or more living cells interact in a specific way, cell surface carbohydrates will be involved.”

- Dr. John Hodgson^[1]

Intercellular communication, the manner in which cells communicate with one another, is a hot scientific topic. This is especially true in the health sciences where cellular communication and cellular recognition is being researched for its ability to influence a person’s health status. There are many links between cell signaling errors and degenerative and autoimmune diseases.^[2] Intercellular communication (cell signaling) is a fairly new field of study which is supported by very little information. This is rapidly changing, however.

Please note that this article is a mere introduction to this highly complex topic. It is intended to be a basic overview of intercellular communication. There are different ways in which communication takes places between cells and entire textbooks could be devoted to each one.

Four Primary Forms of Intercellular Communication in the Human Body

These are the four most common ways in which human cells communicate:

Cell to Cell Contact

Cell-to-Cell Contact Cells respond to intercellular contact (cell-to-cell or extracellular-matrix-to-cell).^[3] These interactions usually occur through glycoproteins^[4] (a protein coated with monosaccharides^[5]) on the surface of the cells’ membranes. Through contact, cells can receive structural and functional signals. Through contact, a skin cell, for example, “knows” that it’s on the surface of your body and not inside, like a heart cell. Through contact, cells can even instruct cells to undergo apoptosis (programmed cell death).^[3]

Proteins

Proteins are secreted from a cell, travel a very short distance (usually to a neighboring cell) where they are recognized and interpreted. These signals can tell one cell to become a skin cell and a nearby cell to become a hair cell (a process called differentiation).^[6]

Hormones

Hormones are considered long range signals. These are created by glands of the endocrine system, they are secreted into the blood stream and distributed to the necessary organs.^[6][7] Hormones play an important role in development, sexual development in puberty, sexual appetite, sleep, maintaining body temperature, metabolism, and just about every major function in your body. There are long-range proteins that are sometimes thought of as hormones, insulin is a good example.^[8]

Electrical and Chemical Signals

Synapse Electrical and chemical signals are responsible for communicating extremely complex messages between neurons or between neurons and muscles cells.^[9] The point of contact between a neuron and another cell (neuron-nueron or neuron-muscle) is called a synapses^[10] and is where electrical signals are converted into a chemical signal, and then back into an electrical signal in the other cell.^[11] These signals are very interesting and may be responsible for learning, memory^[12] and ultimately consciousness.

References:

[1] Hodgson, John. “Capitalizing on Carbohydrates.” Bio/Technology Vol.8(1990).

[2] Systems Biology at Pacific Northwest National Laboratory. “Cell Signaling.” Available at: http://www.sysbio.org/sysbio/cellsignaling.stm.
Accessed August 13, 2008.

[3] Bates, RC. “Apoptosis Induced by Inhibition of Intercellular Contact.” The Journal of Cell Biology, Vol 125, 403-415 (1994). Available at: http://www.jcb.org/cgi/content/abstract/125/2/403.
Accessed August 13, 2008.

[4] Zhao, Runxiang. “Cell Surface Glycoprotein PZR Is a Major Mediator of Concanavalin A-induced Cell Signaling.” J. Biol. Chem, Vol.277, Issue 10. March 8,2002. pp7882-7888. Available at http://www.jbc.org/cgi/content/abstract/277/10/7882.
Accessed August 12, 2008.

[5] MedicineNet.com. Available at http://www.medterms.com/script/main/art.asp?articlekey=16842.
Accessed August 13, 2008.

[6] University of California, San Francisco. “Mechanisms of Cell Communication.” Available at: http://cellbio.ucsf.edu/papers/chapter%2015_02mar07.pdf.
Accessed August 13, 2008.

[7] Wikipedia. “Cell Signaling.” Available at: http://en.wikipedia.org/wiki/Cell_signaling.
Accessed August 13, 2008.

[8] WiseGeek. Available at http://www.wisegeek.com/what-are-hormones.htm

[9] UCIrvine. “Anatomy 101: Spinal Cord and Central Nervous System.” Avialable at: http://www.reeve.uci.edu/anatomy/scns.php.
Accessed: August 13, 2008.

[10] Dictionary.com. Available at: http://dictionary.reference.com/browse/synapses.
Accessed: August 13, 2008.

[11] Stufflebeam, Robert. “Neurons, Synapses, Action Potentials, and Neurotransmission.” Consortium on Cognitive Science Instruction (CCSI). Available at: http://www.mind.ilstu.edu/curriculum/neurons_intro/neurons_intro.php.
Accessed August 13, 2008.

[12] International Science Grid This Week (ISGTW). “Image of the Week – Studying the Process of Learning.” Available at: http://www.isgtw.org/?pid=1000439.
Accessed August 13, 2008.