Qhov sib txawv tseem ceeb ntawm G protein-linked receptors thiab enzyme-txuas receptors yog tias G protein-txuas receptors khi nrog ib qho ntxiv cellular ligand thiab qhib lub membrane protein hu ua G-protein thaum enzyme-txuas receptors khi nrog ib qho extracellular. ligand thiab ua rau kev ua haujlwm enzymatic ntawm sab intracellular.
Nyob hauv cov kab mob ntau lub cev, cov hlwb sib txuas lus nrog ib leeg ntawm cov cim tshuaj. Cells xa lus thiab tau txais cov lus. Los ntawm cov lus no, tag nrho cov dej num uas tshwm sim hauv lub cev yog sib koom ua ke. Paracrine, endocrine, autocrine, thiab kev taw qhia ncaj qha yog plaub yam tseem ceeb ntawm cov xovtooj ntawm tes. Cells tau txais cov cim los ntawm receptors. Cov receptors no tuaj yeem yog intracellular receptors lossis cell nto receptors. Intracellular receptors muaj nyob rau hauv cytoplasm, thaum lub cell nto receptors nyob rau sab nrauv ntawm lub cell membrane. Muaj peb yam tseem ceeb ntawm cell nto receptors li ion channel txuas receptors, G protein-linked receptors thiab enzyme-linked receptors.
G Protein Linked Receptors yog dab tsi?
G protein-linked receptors yog ib hom transmembrane proteins. Raws li lawv lub npe qhia, cov receptors ua haujlwm nrog G proteins uas koom nrog GTP. GTP yog molecule zoo li ATP uas muab lub zog rau G proteins ua haujlwm. Thaum ib lub ligand khi nrog G protein-txuas receptor, nws dhau qhov kev hloov pauv hauv txoj hauv kev uas nws tuaj yeem cuam tshuam nrog G protein.
Daim duab 01: G Protein-linked Receptors
Daim ntawv tsis muaj zog ntawm G protein hloov mus rau hauv daim ntawv nquag thiab faib ua ob daim (alpha thiab beta subunits) los ntawm kev hloov GTP rau hauv GDP thiab siv lub zog tso tawm. Cov subunits no sib cais los ntawm G protein-coupled receptor thiab cuam tshuam nrog lwm cov proteins kom ua rau cov lus teb ntawm tes. Structureally, G protein-coupled receptors muaj xya transmembrane domains uas hla hla daim nyias nyias.
Dab tsi yog Enzyme-Linked Receptors?
Enzyme-linked receptors yog lwm hom cell nto receptors lossis transmembrane receptors. Thaum ib lub ligand extracellular khi nrog ib qho enzyme-txuas receptor, qhov kev khi no ua rau kev ua kom muaj zog hauv lub cell. Ib qho enzyme activates thiab teeb tawm ib txoj kab ntawm cov xwm txheej hauv lub cell uas nws thiaj li ua rau cov lus teb. Yog li ntawd, cov receptors no muaj ib qho chaw intracellular uas koom nrog ib qho enzyme. Qee zaum, qhov no intracellular domain nws tus kheej ua haujlwm raws li enzyme, lossis nws cuam tshuam ncaj qha nrog ib qho enzyme. Raws li kev tsim qauv, cov enzyme-txuas receptors muaj cov loj extracellular thiab intracellular domains thiab ib daim nyias nyias ntawm ib cheeb tsam alpha-helical.
Daim duab 02: Enzyme-linked Receptors
Receptor tyrosine kinase yog ib qho enzyme-txuas receptor. Nws yog ib hom receptor protein koom nrog feem ntau ntawm cov xov tooj ntawm tes taw qhia txoj hauv kev. Raws li nws lub npe implies, receptor tyrosine kinases yog kinase enzymes. Kinase yog ib qho enzyme uas catalyzes kev hloov ntawm phosphate pawg mus rau lub substrate. Cov receptors no muaj tyrosine kinases uas hloov ib pawg phosphate los ntawm ATP rau tyrosine.
Receptor tyrosine kinase muaj ob lub monomers zoo sib xws. Thaum ib qho kev taw qhia molecule khi nrog qhov chaw khi ntawm cov receptor, ob lub monomers tuaj ua ke thiab tsim ib qho dimer. Tom qab ntawd, kinases phosphorylate ATP thiab ntxiv phosphate pawg rau txhua ntawm rau tyrosines. Li no, dimer dhau los ua phosphorylated, uas yog tag nrho activated tyrosine kinase. Activated tyrosine kinase xa cov teeb liab mus rau lwm cov molecules ntawm lub cell thiab mediates teeb liab kis. Cov yam ntxwv tseem ceeb tshaj plaws ntawm receptor tyrosine kinase yog tias nws tuaj yeem qhib ntau txoj hauv kev, thiab thaum nws qhib, nws tuaj yeem tsim ntau cov lus teb ntawm tes ib zaug.
Dab tsi zoo sib xws ntawm G Protein Linked Receptors thiab Enzyme-Linked Receptors?
- G protein-linked receptors thiab enzyme-txuas receptors yog ob pawg ntawm cov cell nto receptors.
- YLawv yog cov proteins transmembrane.
- Lawv yog tshwj xeeb rau ib hom ntawm tes.
- Thaum pib, lawv nyob twj ywm tsis ua haujlwm thiab tom qab ntawd ua haujlwm thaum khi ib lub ligand rau cov receptor.
Qhov txawv ntawm G Protein Linked Receptors thiab Enzyme-Linked Receptors yog dab tsi?
G protein-linked receptors yog cov cell nto receptors uas qhib G cov proteins thaum khi nrog ib qho ligand extracellular. Nyob rau hauv sib piv, enzyme-txuas receptors yog lub cell nto receptors uas qhib nrog ib tug enzyme thiab teev tawm ib tug saw ntawm cov xwm txheej nyob rau hauv lub cell. Yog li, qhov no yog qhov sib txawv tseem ceeb ntawm G protein-txuas receptors thiab enzyme-txuas receptors. Ntxiv mus, G protein-linked receptors muaj xya transmembrane domains hla lub membrane thaum cov enzyme-txuas receptors muaj ib daim nyias nyias-kho ib cheeb tsam alpha-helical.
Cov hauv qab no infographic muab ntau qhov sib piv hais txog qhov sib txawv ntawm G protein-txuas receptors thiab enzyme-txuas receptors.
Summary – G Protein Linked Receptors vs Enzyme-Linked Receptors
G protein-linked receptors thiab enzyme-linked receptors yog ob hom transmembrane receptors. G protein-linked receptors khi nrog ib qho kev sib txuas ntxiv ntawm tes thiab ua kom lub cev nqaij daim tawv hu ua G protein. G protein activation ua rau cov lus teb ntawm tes. Ntawm qhov tod tes, cov enzyme-txuas receptors khi nrog cov ligands extracellular thiab qhib cov enzymes uas ua rau cov saw ntawm cov xwm txheej hauv lub xov tooj ntawm tes uas nws thiaj li ua rau cov lus teb. Yog li ntawd, lub intracellular domains ntawm cov receptors koom nrog enzymes. Yog li, qhov no yog cov ntsiab lus ntawm qhov sib txawv ntawm G protein-linked receptors thiab enzyme-linked receptors.
