Unit 4 Cell Communication

8/9/2019 Unit 4 Cell Communication

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Big Idea 3Living systems store,retrieve,

transmit and respond toinformation essential to life

processes.


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EnduringUnderstanding 3.DCells communicate bygenerating,

transmitting and receivingchemical signals.


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Essential no!ledge3.D"#$3.D." Cell communicationprocesses share commonfeatures that re%ect a shared

evolutionary history

3.D.& Cell communicate !ith each

other through direct contact !ithother cells or from a distance viachemical signaling.


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Essential no!ledge3.D"#$3.D.3 'ignal transductionpath!ays lin( signalreception !ith cellularresponse

3.D.& Changes in signaltransduction path!ays canalter cellular response


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Essential no!ledge3.D"#$3.D.3 'ignal transductionpath!ays lin( signalreception !ith cellularresponse

3.D.& Changes in signaltransduction path!ays canalter cellular response


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)*E+*IE )- CELL'I/0LI/


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Overview of Cell ignaling


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Cell ignaling: tage !

"eception#in$ing of a c%emical messenger

&ligand' coming from outsi$e t%e cell to a receptor protein on t%e

surface of( or insi$e( t%e cell

e)ample of speci1city


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Cell ignaling: tage *

+rans$uctionProcess #y w%ic% t%e c%emical

message is converte$ into acellular response often involves a signal

transduction pathway &se,uence of c%anges in a seriesof $i-erent molecules'


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Cell ignaling: tage

"esponse +%e cell/s reaction to t%e

c%emical message 0 usually ac%anges in t%e cell/s meta#olicactivity

e). enzyme activation( rearrangement of t%e cytos1eleton(

turning on2o- a gene


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A 3 l f C ll


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An 3)ample of Cellignaling

+eception2ransducti

on

+esponse

+esponse


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E24)D' )-

C)U/IC02I)/BE2EE/ CELL'

C ll t C ll &5i t'


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CelltoCell &5irect'ContactE5ample "6 7lant7lasmodesmata

C ll t C ll &5i t'


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CelltoCell &5irect'Contact

E5."6 7lant 7lasmodesmata c%annels t%at connect a$6acentplant

cells7 cytoplasm 8ows #etweencells

water( small solutes( proteins 9"A can pass #etween cells

create a ;living continuum< wit%int%e plant

C ll t C ll &5i t'


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CelltoCell &5irect'ContactE5ample "6 7lant7lasmodesmata

C ll t C ll &5i t'


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E5. & 0nimal ap 8unctions protein c%annels t%at

connect a$6acent animal cells small molecules( inclu$ingions( sugars( amino aci$smove #etween cells

C ll t C ll &5i t'


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E5. & 0nimal ap 8unctions communication #etween

%eart cells

Cell to Cell &5irect'


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E5. 3 Immune Cells


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=ocal ignaling

E5. " 7aracrine 'ignaling"elease of signals t%at act onnear#y cells


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=ocal ignaling

E5. " 7aracrine 'ignaling>rowt%

factors

stimulate

cell

$ivision


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=ocal ignaling

E5. & 7aracrine 'ignaling


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=ocal ignaling

E5. 3 'ynaptic 'ignaling #etween * nerve cells&neurons'

uses c%emical signals calle$neurotransmitters


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=ocal ignaling

E5. 3 'ynaptic 'ignaling


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=ocal ignaling

E5. 3 'ynaptic 'ignaling

=ong 5istance


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=ong 5istanceignaling

Endocrine 'ignaling specialize$ glan$s pro$ucec%emical signals calle$

hormones %ormones travel in t%e blood to t%eir target cells2organs

=ong 5istance


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=ong 5istanceignaling


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EC40/I'' )-CELLC)U/IC02I)/


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Mec%anisms of Cell Communication:Use 5i-erent "eception?

ater'olu

ble

Li

pid'oluble


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Mec%anisms of Cell Communication:An$ $i-erent response mec%anisms.

ater'olu

ble

Li

pid'olu

ble


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'I/0LI/ 7024096+ECE72I)/

"eception of t%e


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"eception of t%eignalignaling #egins wit% t%erecognition of a ligand &c%emical messenger' #y a

receptor protein5i-erent receptors recognize$i-erent ligan$s &s%apesmust matc% to function'

t%is is an e)ample of

speci1city

"eception of t%e


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"eception of t%eignal

Bin$ing of t%e messenger tot%e receptor causes t%es%ape of t%e receptor to

c%ange( #eginning t%e ne)tstage 0 signal trans$uction


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=ocation of "eceptors

":Intracellular +eceptors in t%e cytoplasm O"

nucleus

small( %y$rop%o#icmolecules

&ie. steroi$s( nitrous o)i$e' t%ese receptors often

complete

signal trans$uction as well


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ormone&testosterone'

3+"AC3==U=A"=UD5

"eceptorprotein

5A

m"A

UC=3U

CE+OP=AM

Plasmamem#rane

ormonereceptorcomple)

ew protein

-igure "".;

" +%e steroi$ %ormone testosterone passes

t%roug% t%e plasma mem#rane.

+%e #oun$ protein

stimulates t%e transcription of t%e geneinto m"A.

$

+%e m"A is translate$into a speciFc protein.

<

+estosterone #in$s to a receptor protein in t%e cytoplasm( activating it.

&

+%e %ormonereceptorcomple) enters t%e nucleus an$#in$s to speciFc genes.

3

Dntracellular "eceptor: +estosterone


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=ocation of "eceptors

&: embrane +eceptors in t%e cell mem#rane

%y$rop%ilic &watersolu#le'signals

&ie. proteins( pepti$es(

amines ' t%ese receptors triggermultistep

signal trans$uction


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+ypes of Mem#rane "eceptors

": #protein lin(edreceptors

&: +eceptor tyrosine

(inases3: Ion channel receptors


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Mem#rane "eceptors:

>proteinlin1e$ receptors

Mem#rane receptor is lin1e$ to a?

#proteins:

proteins activate$ #y t%e transferof a p%osp%ate from a molecule of>+P

t%is is t%e Frst step in a protein relay


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"eceptor O+ #oun$ to signal>5P is attac%e$ to > protein G

> protein in DAC+DH3

"eceptor #in$s to signal 9activate$ receptor attac%es to >

protein>+P can #in$ to >protein GAC+DHA+35

Activate$ >proteintransfers to a mem#rane#oun$ inactive enzyme(

AC+DHA+D> t%is enzyme(tri erin a si nal trans$uction

>+P >5P( an$ t%e >protein#ecomes DAC+DH3 once again


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Mem#rane "eceptors:

>proteinlin1e$ receptors

Uses

em#ryonic $evelopment

sensory reception &vision2smell in

%umans'

Dnvolve$ in $iseases &c%olera( pertussis(#otulism' 0 #acteria to)ins interefere w2

>protein function IJ of me$icines in8uence >protein

pat%ways

Mem#rane "eceptors


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Mem#rane "eceptors:

receptor tyrosine 1inases

inases6 a protein t%at a$$s a p%osp%ateto anot%er molecule &; phosphorylates< it'

2yrosine inases6# proteins t%at form $imers

parts of t%e tyrosine molecule transfer

of p%osp%ates to relay proteins

remain active as long as ligan$ is

attac%e$


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DAC+DH3 tyrosine 1inase monomers

=D>A5 #in$s7 tyrosine1inase 5DM3" forms

tyrosine 1inase is AC+DHA+35as p%osp%ate groups are

attac%e$ from A+P

A5P

DAC+DH3 relay proteins #in$to tyrosine 1inase an$ are

AC+DHA+35

Mem#rane "eceptors:


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Mem#rane "eceptors:

receptor tyrosine 1inases

One activate$ tyrosine 1inasemolecule can activate !JLtrans$uction pat%ways an$2orcell responses

aulty tyrosine 1inase receptors

can %ave a wi$esprea$ a-ecton cell function

Mem#rane "eceptors:


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Mem#rane "eceptors:

ion c%annel receptors

Dncoming ions trigger t%e response Act li1e a ;gate< w%en t%e

receptor c%anges s%ape

Use$ in synaptic signaling in t%enervous system7 some arecontrolle$ #y electric( rat%er t%an

c%emical( signals


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Don c%annel is DAC+DH3&ligan$ is un#oun$'

=igan$ #in$s7 receptorc%anges s%ape an$ ionsare allowe$ to cross t%emem#rane

=igan$ is release$7 Donc%annel is DAC+DH35&;gate< closes'Dons stop crossing

mem#rane


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'I/0LI/ 7024096'I/0L2+0/'DUC2I)/


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ignal +rans$uctionProcess #y w%ic% a signal is

converte$ to a cellular response

triggere$ #y t%e #in$ing of t%e

receptor to its speciFc ligan$

involve signaling casca$es t%atrelay

message to intracellular targets

signal is often ampliFe$ along t%eway

often use second messengers

ignal +rans$uction:


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ignal +rans$uction:

econ$ Messengers small( nonprotein( watersolu#le

molecules or ions t%at are part oft%e signal casca$e

Are use$ in signal pat%waysstarte$ #y >lin1e$ proteinreceptors an$ receptor tyrosine

1inases @i$ely use$ inclu$e: cyclic07 an$ Ca&= ions

econ$ Messenger: Cyclic


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econ$ Messenger: CyclicAMP

• A$enylyl cyclase &foun$ in cell

mem#rane' converts A+P into cyclic AMP.• Cyclic AMP is inactivate$ #yp%osp%o$iesterase(

forming AMP.

econ$ Messenger: Cyclic


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econ$ Messenger: CyclicAMP

0n


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0nE5ample6

Cholera

5iarr%ea(vomiting 9$eat% from

$e%y$ration

econ$ Messenger: Ca*L


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econ$ Messenger: Caions• use$ in muscle contraction(secretion of certain su#stances an$ cell

$ivision• concentration in cytoplasm is normally low &1ept t%at way

using protein pumps'• Ca*L levels increase in

res onse to a



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econ$ Messenger: Caions



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econ$ Messenger: Caions• Ca*L levels increase inresponse to a signal trans$uction pat%way7

release$ from t%e 3" in response toot%er *n$

messengers &DP an$ 5A>'



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econ$ Messenger: Caions

P% % l ti


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P%osp%orylation

Casca$es A series of protein(inases a$$ a p%osp%ate

group to t%e ne)t protein int%e casca$e se,uence(lea$ing to t%e triggering of

t%e cell/s response

igure !! in your te)t#oo1


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igure !!. in your te)t#oo1


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'I/0LI/ 7024096CELL +E'7)/'E


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+ypes of "esponses

CytoplasmicC%anges to a cell

process

3)amples: open2close ion c%annels activate an

enzyme trigger cytos1eleton activity

/uclear c%anges in genee)pression &genes areturne$ on or o- tosynt%esize nee$e$

proteins in t%e cell'3)amples:

growt% factors

mating p%eromones

in yeast

cAMP levels regulate

gene e)pression in

#acteria


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2ypes of+esponses6Cytoplasmic


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2ypes of+esponses6/uclear


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An Dllustrative 3)ample:

3pinep%rine

3 i % i


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3pinep%rine

a.1.a. a$renalinecommon %ormone inverte#rates

Dnvolve$ in s%ortterm stressresponse 1nown as ;Fg%t or8ig%t<

3 i % i " t


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3pinep%rine "eceptor

epinep%rine is a polar( amine ligan$ &watersolu#le7 must use mem#rane

receptor' "eception: epinep%rine #in$s to a>proteinlin1e$ receptor em#e$$e$in t%e cell mem#rane

activate$ >protein triggers s%ape

c%ange in a$enylyl cyclase&enzyme'

3 i % i " t


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ignal +rans$uction: a$enylyl cyclase convertsA+P

t%e *n$ messenger cyclic AMP t%is triggers anot%er protein

&1inase A' lea$ing to a

p%osp%orylation casca$e

3 i % i " t


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Cell "esponse: &in t%e liver' glycogen stores glucose

&glucose glycogen in%i#ite$'

'2)7 > 24I/??

@%y $o you nee$ t%e e)tra

glucoseN

E i h i 'i li 7 th


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Epinephrine 'ignaling 7ath!ay

ame ignal 5i-erent


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ame ignal( 5i-erent"esponse5i-erent 1in$s of

cells %ave $i-erentreceptors t%at canrespon$ to t%e

same signal

5i-erent responses

triggere$ #y t%esame

ligan$

same signal( samereceptor( #ut$i-erent signaltrans$uction

pat%way

5i-erent responsestriggere$ #y t%e

same ligan$

)+

3pinep%rine


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3pinep%rine& 9 norepinep%rine'

+%ings get complicate$


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+%ings get complicate$,uic1ly?

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Unit 4 Cell Communication

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