Chapter 11Cell Communication

By: Jenna Alma, Robyn Alma, Nicole Anichich, Sarika Arora, AnaCristina Bedoya, Renee Grasso, Victoria Matiatos, and Danielle Sudol

Let’s Play Telephone!

Cell Signaling

•Cell-cell communication is the way cells “talk” to each other

•Mating yeast cells: a cell and α cell•a factor- signaling molecule that can bind

to specific receptor proteins•a cells secrete this and send them to

nearby α cells•at the same time α cells secrete an a

factor and send them to bind to a cells

•Transduced- the changing of a received signal into a form usable to initiate a cellular response

•This form of cell signaling results in the fusion, or mating, of the two cells where each cell has genes from both original cells.

•Signal transduction pathway- a series of steps that converts a received signal into a specific cellular response

•Ex. Mating yeast cells• -Occurs in animal cells as well

•Quorum sensing- the regulation of local density by bacterial cells by the secretion of small molecules that are detected by nearby bacterial cells

• - Allows the cells to coordinate their production efforts

•Biofilm- a collection of bacterial cells that adhere to a surface to derive nutrients from it

•Ex. Teeth enamel•-caused by quorum sensing

Local and Long Distance Signaling•Cells in multicellular organisms

communicate via chemical messengers

Types of Local Signals:o Direct Contact o Parascine Signalingo Synaptic Signaling

Types of Long-Distance Signals:o Endocrine Signaling

Local Signaling•Direct Contact- the cytoplasms of adjacent

cells are connected by cell junctions o Animal cells can communicate through cell-

cell recognition where membrane-bound cell-surface molecules come in contact

•Local Regulators- influence cells in the vicinity and are secreted by the signaling cell

o Growth factors- a class of local regulators which consist of compounds that stimulate nearby cells to grow and divide

•Paracine Signaling- occurs in animals where many cells simultaneously receive and respond to the molecules of growth factor produced in their vicinity

•Synaptic Signaling- an electrical signal along a nerve cell that triggers the secretion of neurotransmitter molecules which then diffuse across the synapse

o occurs in animal cells

Long-Distance Signaling •Endocrine Signaling- special cells release

hormone molecules which travel by the circulatory system to other parts of the body and reach their target cells

o A.K.A. Hormone Signaling o Hormones- chemicals that are used by

animal and plant cells in long distance-signaling

o Vary widely in size and shape

• The transmission of a signal through the nervous system is an example of long-distance signaling

The Three Stages of Cell Signaling •E.W. Sutherland's work was the first

thorough study of cell signaling• Breakdown of glycogen in our liver and

skeletal muscles is driven by the breakdown of the animal hormone epinephrine

• Epinephrine functions:•     Drives process of glycolysis •     Stores fuel to be secreted when body is

mentally or physically stressed

•- Epinephrine doesn't just work by itself, it requires:

•    • Activation of a cytosolic enzyme•   • Interaction with other cells and the

plasma membrane •WHY? CELL SIGNALING

•STAGE 1: Reception• A signal molecule binds to a receptor

protein• Takes place in cell membrane or inside

cell• Enacts "detection" of chemical signal

•STAGE 2: Transduction• Binding to receptor changes it somehow,

which triggers a series of reactions down a series of different molecules (the signal transduction pathway)

• Relay molecules are spread out on pathway

•STAGE 3: Response• Specific cellular activity is triggered by

the transduced signal• Could drive processes such as activation

of specific genes, catalysis, or rearrangement of cytoskeleton

Thank You!