BIO230H1 Lecture Notes - Lecture 9: Receptor Tyrosine Kinase, Sh2 Domain, Sh3 Domain
BIO230
Lecture 9
Signalling'through'enzyme-coupled'receptors'
'
ENZYME-COUPLED'RECEPTORS'
'
a) !"#"$%&'()*'&+,-"(.,-/+"'–'transmembrane'protein'which'consists'of'two'
domains:'extracellular'domain'which'acts'as'a'receptor'and'binds'a'lingand'and'
intracelular'domain'which'acts'as'an'enzyme'tyrosine'kinase'and'intiated'
intracellula'response.''
'
)'/-+/0%&$1&+$1&'*2/%,&-(–'once'tyrosine'kinase'is'activated,'its'domain'phosphrylate'
each'other''
'
Phosphorylated'receptro'tyrosine'kinase'recruit'protiens'which'mediate'sownstream'
signalling''
345(6&7/,-8(9):(6&7/,-(–'domains'of'recruited'proteins'that'bind'to'phosphotyrosine'
and'neighbouring'sequences.''
'
9;<=('"#"$%&'(–'transmembrane'receptor'is'an'example'of'protien'which'recruits'
proteins'once'phosphorylated.''
The'phosphate'is'recruited'to'the'Tyr'residues'based'ont'eh'presence'of'SH2'domains.'But'
the'protein'can'also'contain'additional'domains'(34>(6&7/,-'which'acts'as'an'adaptor'
and'binds'Pro-rich'sequences)''
'
?77/%,6,07(–'units'from'which'the'eye'of'Drosophila'is'composed'of.'An'ommatidium'
contains'8'photoreceptor'cells,'whcih'are'surrounded'by'12'support'cells.'They'arise'from'
a'simple'epithelial'shhet'through'the'sequential'differnetiation'of'the'photoreceptor'cells.''
Ommatidia'allow'the'animal'to'look'at'different'directions.''
'
!@($1&%&'"#"$%&'(#"22'–'one'out'of'8'photoreceptor'cells'in'the'ommatidium,'responsible'
for'detection'of'UV'light.''
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Core,components,of,receptor,tyrosine,kinase,signalling,pathway:,
- identified'performing'an'experiment'with'R7'photoreceptor'cells'with'the'intensity'
of'UV'light.'Components'(mutants)'failed'to'specify'R7.'
'
MUTANT,1,
3"A"-2"++(B3"AC(D(a'receptor'tyrosine'kinase'itself,'which'is'located'on'the'
membrane'of'R7'photoreceptor'cells.'SH2'domains'of'adaptor'proteins'bind'to'the'
kinase'domain'of'Sev.''
'
MUTANT,2,
(((((((((((((:',6"E&FE+"A"-2"++(B:&++C(–'the'ligand'of'Sev'which'is'expressed'on'the'domain'of'
the'R8'photoreceptor'cell,'which'is'adjacent'to'R7'cell.'
'
,
,,,,,,,,,,,,,,MUTANT,3,
(((((((((((((;'G'–'adaptor'protein,'links'Sev'and'Sos.''
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BIO230H1 Full Course Notes
Verified Note
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Document Summary
Enzyme-coupled receptors: receptor tyrosine kinase transmembrane protein which consists of two domains: extracellular domain which acts as a receptor and binds a lingand and intracelular domain which acts as an enzyme tyrosine kinase and intiated intracellula response. Transautophosphorylation once tyrosine kinase is activated, its domain phosphrylate each other. Phosphorylated receptro tyrosine kinase recruit protiens which mediate sownstream signalling. Sh2 domain, ptb domain domains of recruited proteins that bind to phosphotyrosine and neighbouring sequences. Pdgf receptor transmembrane receptor is an example of protien which recruits proteins once phosphorylated. The phosphate is recruited to the tyr residues based ont eh presence of sh2 domains. But the protein can also contain additional domains (sh3 domain which acts as an adaptor and binds pro-rich sequences) Ommatidium units from which the eye of drosophila is composed of. An ommatidium contains 8 photoreceptor cells, whcih are surrounded by 12 support cells. They arise from a simple epithelial shhet through the sequential differnetiation of the photoreceptor cells.
