cell signaling

there are a lot of different - pathways

cell signaling

information can come in a variety of forms: cellular communication involves

cellular communication involves converting those signals from one form to another

signal transduction

the process of converting an extracellular signal into an intracellular signal to elicit a specific cellular response

cell communication

typical communication between cells

signaling cell produces a signal molecule that is detected by a target cell

target cells have receptro proteins that recognize and respond to the signal molecule

signal transduction begins

when the receptor protein on the target cell received an incoming extracellular signal and converts it to an intracellular signal

Extracellular signal molecules stimulate

a target cell by binding to its receptor proteins, including intracellular and cell-surface receptors

general principles of cell signaling slide

extracellular signals can act _ or -

slowly or rapidly

cell signals can act over a - or - range

long or short

long range signals and commication:

endocrine, synaptic/neuronal

endocrine:

hormones are carried in the blood to distant target cells

synpatic/neuronal:

transmitted along axons to remote target cells

Short-Range signals and communication:

paracrine, contact-dependent

paracrine

signals released by cells into extracellular fluid act locally

contact dependent

direct communication through cell-cell contact

cell signaling slide

endocrine is ‘‘_” style of communication

public

endocrine system works how

broadcasts a signal (hormones) throughout the whole body through secretion into the blood stream

cells that produce hormones are _ cells

endocrine cells

endocrine slide

When action potentials reach the axon terminal, —- signals get converted into — signals

electrical, chemical signals in the form of neurotransmitters

neuronal/synaptic slide

Paracrine: signal molecules diffuse

locally through extracellular fluid

in paracrine signals he signal molecules remain

in the vicinity of the cell that secretes them

Autocrine signaling:

local mediators that are produced by the cells themselves to promote survival or proliferation

what type of signaling do cancer cells perform

Autocrine signaling

paracrine signaling slide

tumor microenvironment slide

Contact-dependent:

cell makes direct physical contact through signal molecules lodged in the plasma membrane of the signaling cell and receptor proteins embedded in the plasma membrane of the target cell

contact dependent slide

paracrine signaling is

slow

paracrine signaling relies on

signals diffusing into local environment

tumor environment is very

complex and heterogeneous

angiogenesis

the physiological process of forming new blood vessels

cancer cells signal outward to induce

angiogenesis to create blood vessels through tumor

the notch receptor itself is a

transcription regulator

When the membrane-bound signal protein Delta binds to its receptor, Notch, on a neighboring cell, the receptor is

cleaved

When the membrane-bound signal protein Delta binds to its receptor, Notch, on a neighboring cell, the receptor is cleaved The released part of the cytosolic tail of Notch migrates to the

nucleus, where it activates Notch- responsive genes, such as genes that control nerve cell production in fruit flies

notch receptor slide

cells are exposed to a wide variety of

signals

cells of a multicellular organism are exposed to

hundreds of signals in its environement

whether or not a cell responds to a signal depends on

whether it posseses a receptor protein for that signal

cell exposure to signals slide

extracellular signals can bind to

cell-surface receptors or to intracellular enzymes or receptors

Extracellular signals fall into —- categories

two

two categories of extracellular signals

1.Those that are too large or too hydrophilic to cross the plasma membrane
2. Those that are small enough or hydrophobic enough to diffuse across the plasma membrane

Large and/or hydrophilic molecules rely on — receptors

membrane

Small and/or hydrophobic molecules —-

diffuse across the plasma membrane, and bind to intracellular enzymes or intracellular receptor proteins

types of extracellular cell signaling slide

Cell surface receptors relay extracellular signals via

intracellular signaling pathways

1st signal transduction step by receptor proteins

Binds the primary messenger and generates new secondary messengers

Signals get passed downstream from one intracellular signaling molecule to the next until

the response has been completed

relaying extracellular signaling slide

square is _ to triangle

upstream

circle is _ to triangle

downstream

Intracellular signaling pathways perform one or more crucial functions including

1. Relay the signal onward
2. Amplify the signal received
3. Receive signals from multiple intracellular signaling pathways and integrate them
4. Distribute the signal to more than one signaling pathway or effector protein

cell surface receptor slides

intracellular signaling proteins can act as

molecular switches

Molecular switches function to allow signals to switch between i

inactive and active states

Once activated, these proteins can

turn on other proteins in the signaling pathway. They persist in the active state until another switch turns them off

Proteins that act as molecular switches:

Kinases, GTP-binding proteins

molecular switches slide

cell communication review