Qhov sib txawv tseem ceeb ntawm heteromeric G protein thiab monomeric G protein yog tias heteromeric G protein yog ib daim nyias nyias uas muaj feem xyuam nrog G protein ua los ntawm alpha (α), beta (β), thiab gamma (γ) subunits, thaum. monomeric G protein yog ib qho me me me-txuas G protein ua los ntawm tsuas yog ib qho alpha subunit.
G proteins (guanine nucleotide-binding proteins) yog ib tsev neeg ntawm cov proteins uas ua raws li kev hloov pauv hauv cov hlwb. Lawv koom nrog hauv kev xa cov teeb liab los ntawm ntau yam stimuli sab nraum lub cell mus rau sab hauv. G proteins tuaj yeem faib ua ob tsev neeg ntawm cov protein: heteromeric G protein thiab monomeric G protein. Heteromeric G protein yog cov protein ntau, thaum monomeric G protein yog cov protein me me.
Heteromeric G Protein yog dab tsi?
Heteromeric G protein yog G protein loj uas tsim los ntawm alpha (α), beta (β), thiab gamma (γ) subunits. Heteromeric G protein tsim ib heterotrimeric complex. Qhov loj tshaj plaws uas tsis yog qauv sib txawv ntawm heterotrimeric thiab monomeric G protein yog tias heterotrimeric G protein khi rau nws cov cell nto receptor (G protein-coupled receptors) ncaj qha. Lub alpha subunit ntawm heteromeric G protein feem ntau yog txuas rau GTP lossis GDP uas ua haujlwm rau kev qhib lossis kaw rau kev ua haujlwm ntawm G protein.
Daim duab 01: Heteromeric G Protein
Thaum ligands khi rau GPCR, GPCR tau txais GEF (guanine nucleotide exchange factor) muaj peev xwm. Qhov no ua rau G protein los ntawm kev sib pauv GDP ntawm alpha subunit rau GTP. Kev khi ntawm GTP mus rau alpha subunit ua rau muaj kev hloov pauv ntawm cov qauv thiab kev sib cais ntawm alpha subunit los ntawm tus so ntawm G protein. Feem ntau, cov alpha subunit khi cov membrane-bound effector proteins rau cov downstream signaling cascade. Lub beta-gamma complex kuj tuaj yeem ua tiav qhov haujlwm no. Tsis tas li ntawd, heteromeric G proteins koom nrog txoj hauv kev xws li cAMP/PKA txoj hauv kev, ion channels, MAPK, thiab PI3K.
Monomeric G Protein yog dab tsi?
Monomeric G protein yog ib qho me me-txuas nrog G protein uas yog tsim los ntawm tsuas yog ib qho alpha subunit. Cov me me monomeric G protein yog homologous rau alpha subunit ntawm loj heteromeric G protein. Cov tsev neeg ntawm GTPases me me no suav nrog RAS superfamily, uas tau muab faib ntxiv rau hauv subfamilies raws li cov qauv, ntu, thiab kev ua haujlwm zoo sib xws. Ntxiv mus, txhua lub tsev neeg me me ntawm GTPases plays lub luag haujlwm sib txawv me ntsis tseem ceeb hauv kev tswj hwm ntawm intracellular signaling pathways.
Daim duab 02: Monomeric G Protein
Zoo li alpha subunit ntawm loj heteromeric G protein, me me monomeric G protein hloov ntawm ib qho ntawm lub xeev (txheej txheem rau GTP) thiab lub xeev tawm (kwv yees rau GDP). Yog li ntawd, monomeric G proteins ua haujlwm li binary keyboards uas tswj cytosolic signaling pathways. Qhov saum toj no GDP / GTP kev caij tsheb kauj vab yog tswj los ntawm ob hom kev tswj hwm cov protein cuam tshuam nrog monomeric G proteins. Guanine exchange Factors (GEFs) txhawb kev tsim cov nquag lossis GTP khi daim ntawv ntawm monomeric G protein (RAS protein), thaum GTPase activating proteins (GAPs) ua kom cov GTPase kev ua si thiab txhawb qhov tsis ua haujlwm lossis GDP khi ntawm monomeric G protein (RAS protein)
Dab tsi zoo sib xws ntawm Heteromeric G Protein thiab Monomeric G Protein?
- Heteromeric G protein thiab monomeric G protein yog ob hom G proteins.
- Lub alpha subunit ntawm heteromeric G protein yog cov qauv muaj feem xyuam rau cov monomeric G protein.
- Ob leeg cov proteins khi rau GTP thiab hydrolyze rau GDP, yog li ua raws li kev hloov pauv molecular.
- Tus nqi ntawm GTP hydrolysis catalyzed los ntawm ob qho proteins tuaj yeem nce los ntawm GAP proteins.
- Lawv raug khi rau sab hauv ntawm lub plasma membrane los ntawm kev hloov pauv lipid tom qab kev hloov pauv.
Qhov txawv ntawm Heteromeric G Protein thiab Monomeric G Protein yog dab tsi?
Heteromeric G protein yog ib qho loj membrane-txuas G protein ua los ntawm alpha (α), beta (β), thiab gamma (γ) subunits, thaum monomeric G protein yog ib tug me me membrane-kawg G protein ua. ntawm tsuas yog alpha subunit. Yog li, qhov no yog qhov sib txawv tseem ceeb ntawm heteromeric G protein thiab monomeric G protein. Tsis tas li ntawd, heterotrimeric G protein khi rau nws cov cell nto receptors (G protein-coupled receptors) ncaj qha. Ntawm qhov tod tes, monomeric G protein khi rau nws cov cell nto receptors (G protein-coupled receptors) indirectly.
Cov hauv qab no qhia txog qhov sib txawv ntawm heteromeric G protein thiab monomeric G protein nyob rau hauv daim ntawv tabular rau ib sab ntawm kev sib piv.
Summary – Heteromeric G Protein vs Monomeric G Protein
G proteins yog ib tsev neeg ntawm cov proteins uas ua raws li kev hloov pauv hauv cov hlwb. Heteromeric G protein thiab monomeric G protein yog ob hom G proteins. Heteromeric G protein yog ib tug loj membrane-kawg G protein uas muaj alpha (α), beta (β), thiab gamma (γ) subunits. Monomeric G protein yog ib tug me me membrane-txuas G protein uas muaj tsuas yog ib tug alpha subunit. Yog li, qhov no qhia txog qhov sib txawv ntawm heteromeric G protein thiab monomeric G protein.
