Cell Communication
Biology 210 with Dekrey at University of Northern Colorado
About this deck
By: Danea Burgess
Textbook:
Essential Cell Biology
Created: 2010-11-25
Size: 35 flashcards
Views: 111
Textbook:
Essential Cell BiologyCreated: 2010-11-25
Size: 35 flashcards
Views: 111
About StudyBlue
STUDYBLUE makes things that make you better at school.
Things like online flashcards with photos and audio.
Things like personalized quizzes and friendly reminders about when (and what) to study next.
Think of it as a digital backpack™: access to all of your study materials online and on your phone.
STUDYBLUE exists to make studying efficient and effective for every student, for free. Join us.
“I have been getting MUCH better grades on all my tests for school. Flash cards, notes, and quizzes are great on here. Thanks!”
Kathy
Kathy
Sign up (free) to study this.
Types of Cell Signaling
Release of information molecules that can bind to cell receptors.
Cell surface interactions- cell-cell contact required
direct electrical signaling through pores (gap junctions)
Signaling molecule distance
endocrine- short or long distance
paracrine- between neighboring cells
neuronal- across a synapse between two cells
autocrine- signals released and received by same cell
One signal may have different messages...
Different cell types can interpret same signal in different ways
This helps coordinate function throughout the organism
signaling cascades
activation of a receptor starts a multi-step signal cascade.
cellular response can vary with cell type or tissue.
Multiple functions of Signaling cascades
Transduction: to transduce signal from one form into another within a cell or across a membrane.
Relaying: to pass on the signal.
Amplification: to increase number of signaling molecules
Integration and distribution
integration: signals can converge from multiple pathways to modulate a response.
Distribution: cascades can diverge to influence multiple cellular targets.
Functions of Receptors
Sensing information from other cells, environment, food, and danger.
Interpretation of information
Receptors bind ligands
cells typically express many different kinds of receptors or the same receptor.
two categories of signaling molecules
first messenger- ligand that activates a receptor
second messenger- signaling molecule produced or released because of response to first messenger.
can be produced on demand or stored until needed.
Two receptor locations
cell surface- signaling molecule can't enter cell usually
intracellular- small lipophilic signaling molecule.
Two types of intracellular receptors
enzymes that produce second messengers.
nuclear receptors that regulate gene expression.
three types of cell surface receptors
ligand gated ion channels
G-protein coupled receptors
enzyme linked receptors
Two types of intracellular receptors
Nitric Oxide signaling
Nuclear receptors
Nitric Oxide production
NO is produced after neural stimulation.
NO is released as second messenger which crosses membranes into smooth muscle cells.
NO in smooth muscle
NO activates guanilyl cyclase which produces cGMP (2nd messenger).
Smooth muscle relaxation is regulated by cGMP- dependent protein phosphatases.
how is Cyclic GMP regulated
Muscle contraction is controlled by the balance of cGMP production and elimination.
Effects of nuclear receptors
expression of genes impacted.
often associated with significant changes in cellular physiology.
Cellular responses are typically slow- hours to days.
common ligands for nuclear receptors
many steroid hormones, each with different receptors that regulate set of genes.
Ligand gated ion channel: cell surface receptor
common receptors for neurotransmitters.
excitatory receptors facilitate action potential formation
G-protein associated receptors: cell surface
largest eukaryotic family of receptors.
all have similar seven pass transmembrane structure.
all interact with guanine nucleotide binding G-proteins.
Activation of G proteins
Ligand binding activates receptor.
Receptor triggers affinity change for GDP and GTP.
Two major parts of G-protein become active.
Each G-protein subunit mediates signaling.
G protein signaling
both alpha and beta gamma subunit interact with membrane proteins by binding.
G-protein binding regulates the activity of the target protein- up or down.
How G-proteins inactivate
Inactivate themselves.
Alpha subunit has GTPase activity.
GTP hydrolysis turns alpha subunit off.
Reassembly of the G-protein turns of the gamma delta subunit.
What are the targets of Gproteins
More Gproteins than Gprotein associated receptors.
at least 20 different G-protein heterodimers are known, most activated by separate receptors.
Major G-protein Targets
Plasma membrane ion channels
enzymes which produce second messengers.
Most common G-protein second messengers
Cyclic AMP- via activation of adenyl cyclase.
diacylglycerol(DAG) and inositol triphosphate(IP3)
Activation of Second Messengers
activated by adenyl cyclase generates cAMP.
this commonly leads to activation of protein kinases A.
what does cAMP do for protein kinases A
activates them.
PKA then go on to activate additional signals.
cAMP signaling cascades lead to cellular responses.
How are protein kinases regulated
Phosphorylation- by other kinases or self.
Allosterism- cAMP, CGMP, Ca
Location- transport to or isolation from their substrate proteins.
Lots of kinases
about 2% of 30,000 human genes code for kinases.
average mammalian cell contains 100s of distinct protein kinases.
animal protein kinases phosphorylate three amino acids
How are plants different with kinases?
They don't use protein tyrosine kinases.
They do use histidine kinases.
they don't use cyclic-AMP signaling cascades (no PKA)
They don't use steroid nuclear receptors.
Enzyme Linked receptors: cell surface. What are the major subtypes in animals?
receptor kinases- tyrosine kinases, and receptor serine/threonine kinases.
indirect kinase receptors- activated bind to kinases and activate them.
Receptor tyrosine kinases
upon binding ligand receptors dimerize and auto-phosphorylation occurs.
phosphate binding "adaptor" trigger signal transduction.
Indirect Tyrosine kinase receptors
Dimerized receptors bind JAK proteins.
Activation of JAK leads to phosphorylation of receptors.
modified receptors bind to STAT proteins.
Why is signaling cross-talk and integration important?
multiple signals can regulate one signaling cascade which is important for intregration of information. which is important for weak signals that are important to be heeded, and strong but less important signals to be ignored.
About this deck
By: Danea Burgess
Textbook: Essential Cell Biology
Created: 2010-11-25
Size: 35 flashcards
Views: 111
Textbook:
Essential Cell BiologyCreated: 2010-11-25
Size: 35 flashcards
Views: 111
About StudyBlue
STUDYBLUE makes things that make you better at school.
Things like online flashcards with photos and audio.
Things like personalized quizzes and friendly reminders about when (and what) to study next.
Think of it as a digital backpack™: access to all of your study materials online and on your phone.
STUDYBLUE exists to make studying efficient and effective for every student, for free. Join us.
“I have been getting MUCH better grades on all my tests for school. Flash cards, notes, and quizzes are great on here. Thanks!”
Kathy
Kathy