第17章激素及其受體介導(dǎo)信號轉(zhuǎn)導(dǎo)

Chapter

17Hormones

and

their

receptor-mediated

signal

transductionOutline

General

characteristics

of

hormonesHormone

definitionChemical

nature,

classification

and

biosynthesis

ofhormonesQuatitation

of

hormones

General

mechanism

of

hormone

action1.2.3.4.5.SpecificityHigh

efficiencyHydrophilic

hormones

usually

require

second

messengerTrigger

acute

effects

or

chronic

effectsDesensitisation

and

termination

Detailed

mechanism

of

hormone

action

Integration

of

signal

transduction

Hormone

secretion and

its

regulationGeneral

definition

for

hormoneClassic

definition

(

By

Starling

and Bayliss)The

hormones

are

chemical

substancesproduced

by

specialized

tissues

andsecreted

into

blood,

in

which

they

arecarried

to

target

organs

and

triggersspecific

biological

functionsBroader

definitionA

hormone

is

a

chemical

non-nutrient,intercellular

messenger

that

is

effectiveat

micromolar

concentrations

or

lessLimits

of

classic

definition

Specialized

tissues

for

hormone

synthesis

Blood

for

hormone

distribution-pheromone?

A

separate

target

organFurther

Classification

of

Animal

HormonesEndocrineHormoneParacrine

Hormone-Such

as

some

growthfactorsAutocrine

Hormone-Such

as

many

oncogeneproductsIntracrine

Hormone?A

further

understanding

on

hormones Living

things

that

can

secrete

homonesMulticelluar:

Animal,

Plant,

Insect

and

Some

fungiConcentrationPeptidal

hormone

in

animal

blood:10-12~10-10MSteroid

hormone

in

animal

blood:10-10~10-8MEndocrine

cell

and

Target

Cell,

tissue

and

organPowerful

Biological

Effects Metabolism

and

Physiological

effectDetermine

the

concentration

of

hormonesChemical

AssayBioactivity

assayRIA-Radioimmunoassay-Developed

by

R.

YalowDiagrammatic

representation

of

RIAQuantitate

ACTH

by

RIAGeneral

Characteristics

of

HormonesChemical

NatureExtremely

diverseHydrophobic

or

HydrophilicHighly

regulated

secretionPre-hormone→

hormone“Acute

effects”

and

“chronic

effects”A

comparison

of

Hydrophobic

and

Hydrophilic

HormonesCharacteristicHydrophobicHydrophilicExamplesSteroids

andThyroninesPepetidesandCatecholaminesStorage

after

synthesisMinimal

except

forThyroninesYesBinding

proteinsAlwaysUncommon

except

forsmaller

peptidesHalf-lifeLong

(hours

ordays)Short

(minutes)ReceptorsCytoplasmicor

nuclearPlasma

membraneMechanism

of

ActionDirectIndirect

(secondmessenger)Synthesis

of

ligandRelease

of

ligand

from

the

signaling

cellTransport

to

the

target

cellBinding

of

ligand

by

a

specific

receptor,

leadingto

its

activationInitiation

of

one

or

more

signal

transductionpathwaysSpecific

changes

in

cellular

functionRemoval

of

signalSteps

of

Hormonal

Action配體受體第二信使效應(yīng)各級效應(yīng)蛋白效應(yīng)Common

characteristics

of

hormonal

actionHighly

specific:

Receptor

and

LigandHighly

powerful

at

micromolar

concentrationsSecond

messenger:

cAMP,

cGMP,

IP3,

DG,

Ca2+,Ceramide,NOInteraction

between

various

hormonesAcute

effect,

chronic

effectDesensitizationCovalent

modificationDown

regulation

of

receptor

numbersTerminationReceptorsDefinitionNature,

Structure

and

Classification

of

ReceptorsIntracellular

receptorCell-surface

receptor①

G-protein-coupled

receptor

(GPCR

or

7TM)②

Ion-channel

receptor③

Receptors

with

intrinsic

enzymatic

activity④

Receptors

lacking

intrinsic

catalytic

activity

butdirectly

associated

with

cytosolic

protein

tyrosinekinaseFour

major

types

of

membrane

receptorsBinding

Natures

of

Receptorand

LigandHighly

specificHigh

affinityReversibleSaturablePowerful

biological

effectsCyclic

Nucleotide

Metabolism

-

cAMPCascadeorganization

&

amplification

during

Signal

transductionDetailed

Mechanism

of

Hormonal

ActionHydrophobic

hormonesCytosolic

receptor

(cortisol

and

aldosterone)Nuclear

receptor(T3,T4,progesterone

and

estrogen)Plasma

membrane

receptor

(Xenopus’s

progesterone)Hydrophilic

hormonesG

protein

system

(AC

system

and

PI

system)GC

systemNO

systemRTK

systemOther

systemsNuclear

Hormone

Receptor

SuperfamilyZinc-finger

motif糖皮質(zhì)激素受體的DNA結(jié)合結(jié)構(gòu)域與HRE的結(jié)合Mechanism

of

Fat-soluble

Hormone

action

by

Cytosolic

receptorsHistone

acetyltransferaseHRE

consensus

sequences

of

several

hydrophobic

hormonesWhat

are

the

G

proteins?

-

G

protein

meansGuanine

nucleotide-

binding

proteinGs

or

PKA

systemGq

or

PKC

systemOther

G

proteins

systemMechanism

of

Action

of

HydrophilicHormones

requiring

G

proteinsGPCRsIntegral

membrane

proteins7

hydrophobic

domains

=7

transmembrane

helicesSignal

from

outside

to

insideActivate

heterotrimeric

G-proteinsactivates

or

inhibits

an

effector,

e.g.,

adenylyl

cyclase,phospholipase,

or

ionic

channelGPCRs

40%

of

the

drugs

used

clinically

inhumans

target

GPCRs

Fourth

largest

superfamily

inhuman

genome

(>

800

genes)Hormones,

chemokines,

neuro-transmitters,

calciumOdorants,

bitter

&

sweet

taste,

photons

oflightMost

detect

a

small

molecule

or

peptideOpsins

activated

by

photonThrombin

receptor

activates

itselfG-protein-coupledreceptorsGlory

on

GPCRG

protein

相關(guān)諾貝爾獎(jiǎng)項(xiàng):1967年視覺產(chǎn)生；1971年cAMP；1988年P(guān)ropranolol（心臟病治療藥物）的藥理作用:阻斷β-腎上腺素受體的功能；1994年異源三聚體G蛋白[Gilman’s

Experiments

]；2004年嗅覺受體家族及其功能；Discovery

and

Structureof

G

ProteinMartin

Rodbell

and

Alfred

G.

Gilman

(1994Nobel

Laureate)GTP

is

necessary

for

the

action

of

Glucagonon

liver

cyclaseGTP

hydrolysis

during

Glucagon

actionIdentify

and

purify

the

G

protein

by

usinggenetic

and

biochemical

techniquesGilman’s

Experiments

(1)

A

mutated

lymphoma

cell

was

found

to

contain

a

normalreceptor

and

a

normal

cyclic

AMP-generating

enzyme

butwas

yet

unable

to

respond

because

it

lacked

the

transducer.This

was

a

good

system

to

assay

purified

G

proteins.Gilman’s

Experiments

(2)

A

G

protein

could

be

isolated

from

normal

brain

tissue

andinserted

in

the

mutated

cell,

thereby

restoring

its

function.All

GTP-binding

proteins

differ

in

conformationdepending

on

whether

GDP

or

GTP

is

present

attheir

nucleotide

binding

site.

Generally,

GTPbinding

induces

the

active

state.Heterotrimeric

:alpha,

beta,

and

gamma

subunits;alapha

binds

GTPSmall

GTP-binding

proteinsG-proteins

-bind

to

and

hydrolizeGTPabgabgGDPGTPactive

formHeterotrimeric

GTP-bindingProteinsinactive

formHeterotrimeric

G

protein

cycleGEF(ligand-boundreceptor)“ON“OFF”bgbgaabGAP

(RGS)gGEF=

GTP

exchange

factorGAP=

GTPase

activating

proteinHow

is

heterotrimeric

G

proteinlinked

to

the

plasma

membrane?Six

major

G

proteinsSmall

GTP-binding

Proteinsinitiation

&

elongation

factors

(protein

synthesis).Ras

(growth

factor

signal

cascades).Rab

(vesicle

targeting

and

fusion).ARF

(forming

vesicle

coatomer

coats).Ran

(transport

of

proteins

into

&

out

of

the

nucleus).Rho

(regulation

of

actin

cytoskeleton)Gs

orPKA

systemMajor

playersHormones

(glucagon,

Epinephrine)Gprotein:

Gs

-

can

stimulate

adenylate

cyclase(AC)Effector:

ACSecond

messenger:

cAMP-discovered

byEarl

W.Sutherland

(1971Nobel

Laureate)Protein

kinase:

cAMP-dependent

protein

kinase

(PKA)-

discoveredby

E.H.

Fischer

and

E.G.

Krebs

(1992 Nobel

Laureate)Target

proteinsDiagram

and

AnimationcAMP.swfAction

ofEpinephrineActivation

of

PKA

by

cAMPConsensus

sequence

recognized

by

PKAArg-Arg-X-Ser-Z

orArg-Arg-X-Thr-Z X

is

a

small

residueZ

is

a

large

hydrophobic

residueR

chain

contains

a

sequence: Arg-Arg-Gly-Ala-IleThe

pseudosubstrate

sequenceProtein

kinasesAdd

phosphates

to

proteinsInvolved

in

all

signaling

from

cell

surface

receptors, and

in

most

other

signaling

tooTypes:Serine/ThreonineTyrosineDual-specificityHistidineProteinOH

+

ATP

Protein

O

POO-O-+

ADPPiH2OProtein

KinaseProtein

Phosphatase蛋白激酶磷酸酶許多酶的活性受到側(cè)鏈氨基酸殘基磷酸化的調(diào)控Action

of

Epinephrine

on

Liver

CellsCyclic

Nucleotide

Metabolism

-

cAMPPKA的兩種效應(yīng)：快反應(yīng)：細(xì)胞質(zhì)中，磷酸化多種蛋白質(zhì)或酶慢反應(yīng)：細(xì)胞核，磷酸化轉(zhuǎn)錄因子CREBcAMP-elicited

Chronic

effectsTermination

of

the

signalHR*→H

+

RcAMP

is

broken

down

by

phosphodiesteraseGTPasePhosphatase

reverses

the

phosphorylation

of

the three

proteins,I.e.

phosphorylase

kinase,glycogen

synthase

andphosphorylaseActivation/

deactivation

cycles

of

G

proteinGTP

analogues

canprolong

the

actionof

hormones

requiring

GproteinsGsα：GTPase活性Giα：GTP-GDP交換Effects

ofCT

and

PT

on

Signal

TransductionHowdoescoffeeperkyouup?caffeine

inhibits

phosphodiesterase

so

cAMP

levels remain

highphosphodiesterasecAMP

AMPcaffeineadrenalin’s

effect

on

heart

is

prolongedmore

O2

to

brain

&

tissuesgives

a

feeling

of

increased

vitality

and

energya

moderate

“fight

or

flight”

rushPI

System

(PKC

System)Major

playersHormones:

GnRH

(acts

on

Anterior

Pituitary)G

Protein:

GqEffector-

PLC

-βSecond

messenger-DG,IP3

,Ca2+Protein

kinase:

PKC

and

Calmodulin-dependentprotein

kinase

(CaMPK)DiagramAction

of

GnRH

on

its

Target

CellsThe

Structure

and

Function

of

CaM?

Discoverer-AnABC:

Dr.George

Cheung

(1971)?

Structure One

of

Calcium

sensors;

148

aa;

acidic;heat-stable;ubiquitous;

highly

conservativeSpecial

motif-“EF-hand”?

FunctionAct

as

δsubunit

of

Glycogen

Phosphorylase

bActivate

other

proteins

directlyActivate

other

proteins

indirectly

by

CaM-dependent

PKFunctions

of

CaMTermination

of

PI

systemPhorbol

esterHR*→H

+

RGProtein’s

intrinsic

GTPaseDegradation

of

“Second

Messengers”IP3→IP2→IP→I→PI→PIP2Manic

andRemedyPhorbol

ester

-

A

highly

carcinogenicagent)Ca2+

-

calcium

PumpPhosporylated

Protein

PhosphataseOther

GProtein-linkedSystemOlfactory

Signal

Transduction

CascadeVisual

Signal

Transduction

CascadeOlfactory

Signal

Transduction

CascadeMajor

playersFirst

Messenger:

odorantsTarget

Cells:

olfactory

receptor

cellsReceptor:

olfactory

receptorG

Protein:

GolfEffector:

ACSecond

messenger:

cAMPTarget

proteins:

Na+/Ca

2+

channel

and

Cl-

channelDiagramOdorant

Receptors

and

Organization

of

the

olfactory

SystemOlfactory

Signal

Transduction

CascadeIn

brainVisual

Signal

Transduction

CascadeMajor

playersFirst

Messenger:

PhotonsTarget

Cells:

Rod

Cells

or

Cone

CellsReceptor:

Rhodopsin

(Opsin+11-Cis-Retinal)G

Protein:

Gt

(Transducin）Effector:

G-PDESecond

messenger:

cGMPTarget

proteins:

Na+/Cl-

channelDiagramVertebrate

Rod

Cell類比咖啡因茶堿的作用機(jī)制Photochemical

Isomerization

of

RetinalRegulation

of

cGMP-gated

Cation

ChannelChanges

in

Membrane

PotentialPKG

systemNO

systemMechanism

of

Action

of

HydrophilicHormones

without

G

proteinsGC

System

(PKG

System)Major

playersHormone:

ANF

(Atrial

Natriuretic

Factor)Receptor:

receptor

enzyme

with

intrinsic

GC

activitySecond

Messenger:

cGMPProtein

kinase:

cGMP-dependent

kinase

(PKG)DiagramNOSystemNobel

Committee

Says

Yes

to

NOThe

discovery

of

NO

as

a

signaling

moleculeRobert

F.

Furchgott,

Louis

J.

Ignarro,

Ferid

Murad(1998

Nobel

Laureate)SynthesisDiagramDynamite

and

Angina Viagra

and

Impotence(Molecule

of

the

1992

year)一氧化氮參與的過程和疾病神經(jīng)傳遞，記憶力，休克青光眼和神經(jīng)變性血管舒張,血壓,血流肺動(dòng)脈高壓血管再生,傷口愈合動(dòng)脈粥樣硬化炎癥,關(guān)節(jié)炎,腎炎,腸炎胞內(nèi)毒組織,病原體,腫瘤組織移植敗血病休克,低血壓血小板聚集胃腸動(dòng)力激素分泌血紅蛋白傳遞氧干細(xì)胞增殖和分化支氣管擴(kuò)張Nitric

oxidenitric

oxide

(NO)acts

as

a

paracrine signal-only

affectslocal

areashort

t1/2

=

1-5

secsproduced

by

nitricoxide

synthase(NOS) from

the

amino

acid

arginineNOhasrolein:vasodilation

of

blood

vesselskilling

of

bacteria,

parasites

and

tumoursNO

and

vasodilationNO

most

potent

vasodilator

knownproduced

by

endothelial

cells

following

activation

by acetylcholine,

GABA,

adrenalinpasses

from

endothelial

cells

to

smooth

muscles –

passes

thu’

muscle

cells

via

gap

junctionsacetylcholine,

GABA,

adrenalin

acts

as

1st

messenger in

endothelial

cellsNO

acts

as

1st

messenger

in

smooth

muscle

cellscGMP

acts

as

2nd

messngerCa2+

acts

as

3rd

messengerNitric

oxide

synthase

(NOS)

and

the

catalyzed

reaction一氧化氮復(fù)合酶亞型NOS-1(nNOS)神經(jīng)的,腦部的,類型1-NOS;中樞和外周神經(jīng)元,非膽堿非腎上腺素能神經(jīng)元,孤島,子宮內(nèi)膜,骨胳肌肉等等.NOS-2(iNOS)可誘導(dǎo)的,類型II-NOS;巨噬細(xì)胞,肝,平滑肌,內(nèi)皮組織,心臟等;糖皮質(zhì)激素NOS-3(eNOS)內(nèi)皮的,類型III-NOS;內(nèi)皮組織,大腦,心臟等;乙酰化,磷酸化1998年諾貝爾生理醫(yī)學(xué)獎(jiǎng)得主路易斯博士：

解決心腦血管疾病的唯一途徑是提升體內(nèi)的一氧化氮。cGMPPKGCa

2+濃度降低肌球蛋白去磷酸化，松弛血管平滑肌NO-mediated

Vascular

RelaxationVasodilatorydrugs(nitroglyerin

&

nitrites)NO2NO2CH2

CH2

CH2O

O

ONO2

NO

is

active

ingredient

in

nitroglycerinpoweful

drug

for

heart

attack

and

angina

nitroglycerin

also

known

as

trinitroglycerin

(TNT)active

ingredient

in

dynamite

Alfred

Nobel

invented

dynamite,

established

NobelPrizes

with

the

moneysuffered

angina

and

took

nitroglycerinRTK

SystemGeneral

CharacteristicsCloselylinked

to

Growth

factors-EGF, NGF,

FGF,IGF-1,

IGF-2,

PDGF,

CSF,

Insulin

et.,

alReceptors

have

intrinsic

Tyrosine

Protein

Kinaseactivity(TPK)The

most

important

pathway

transmitting

extracellularsignals

into

nuclei

Major

playersLigandsReceptors:

Extracelluar

domain,

trans-membranedomain

and

intracelluar

domainAdaptors

Proteins

-Grb-2orSem-5:

Contain

SH2

and

SH3domains

(

SHmeans

Src

Homology)RTK

System

(continued)Guanine

nucleotide

exchange

factors-

SOS

proteins

(promote GDP/GTP

exchange)Ras

proteins-SpecialG

proteinsVarious

ProteinKinases:

MAPKKK(

Raf)-

Ser/Thr;

MAPKK (Mek)

-Ser/Thr/Tyr

;

MAPK-

Ser/Thr;MAP

means

Mitogen– Activated

ProteinTranscriptions

Factors

(TF)-

Fos,

J