Qhov sib txawv tseem ceeb ntawm GAP thiab GEF yog GAP (GTPase activating protein) yog cov protein uas tuaj yeem tua cov teeb liab qis ntawm cov cell tom qab khi rau G protein, thaum GEF (guanine nucleotide exchange factor) yog protein ntau. tuaj yeem ua rau qis qis qis ntawm lub xovtooj tom qab khi rau G protein.
G cov proteins tseem hu ua guanine nucleotide-binding proteins. G protein yog ib qho protein uas tuaj yeem ua raws li kev hloov pauv hauv molecular hauv lub cell. Nws koom nrog hauv kev xa cov teeb liab los ntawm ntau yam stimuli sab nraum lub cell mus rau sab hauv ntawm lub xov tooj. Tsis tas li ntawd, G proteins yog ib pawg loj ntawm cov enzymes hu ua GTPases. Kev ua haujlwm ntawm G protein yog tswj hwm los ntawm cov yam ntxwv uas tswj lub peev xwm ntawm G protein kom hydrolyze GTP rau GDP. Thaum G protein khi rau GTP, nws ua haujlwm. Tab sis thaum G protein khi rau GDP, nws tsis ua haujlwm. Yog li, GAP thiab GEF yog ob yam uas tuaj yeem tswj hwm txoj haujlwm ntawm G protein.
GAP yog dab tsi?
GTPase activating protein (GAP) yog cov protein uas tuaj yeem tua cov dej ntws tawm ntawm tes tom qab khi rau G protein. Cov protein no tseem hu ua GTPase accelerating protein. Nws tuaj yeem khi rau activated G proteins thiab txhawb lawv txoj haujlwm GTPase. Qhov no ua rau kev txiav tawm ntawm cov xwm txheej downstream signaling. GAP tshem tawm cov teeb meem tshwm sim los ntawm inducing GTP hydrolysis. Thaum nws txhim kho GTP hydrolysis (GTP⇒GDP) cov tshuaj tiv thaiv ntawm G protein, G protein kawg khi nrog GDP. Qhov no inactivates G protein thiab tua lub downstream signaling.
Figure 01: GAP
Nyob rau hauv qhov kev nkag siab no, GAP muaj nuj nqi yog qhov cuam tshuam rau ntawm guanine nucleotide exchange factor (GEF), uas txhim kho G protein-mediated downstream signaling. GAP deregulation feem ntau cuam tshuam nrog cov qog nqaij hlav. Qhov no yog vim qhov tsis ua haujlwm ntawm GAPs cuam tshuam nrog G proteins lossis poob ntawm G protein lub peev xwm los teb rau nws GAP.
GEF yog dab tsi?
Guanine nucleotide exchange factor (GEF) yog ib qho protein uas tuaj yeem ua rau qis qis qis ntawm tes tom qab khi rau G protein. Nws yog cov protein los yog cov protein ntau uas koom nrog hauv kev ua kom cov GTPases me (G proteins). Feem ntau, GDP dissociates los ntawm inactive G proteins qeeb heev. Kev khi ntawm GEF rau G protein catalyzes dissociation ntawm GDP, tso cai rau GTP molecule los khi rau hauv nws qhov chaw.
Figure 02: GEF
Ntxiv mus, kev khi ntawm GTP rau G protein molecule ua rau kev tso tawm GEF. Yog li, nws activates G protein molecule thiab G protein-mediated downstream cell signaling. Tsis tas li ntawd, qee qhov GEFs tuaj yeem qhib ntau G proteins thaum lwm tus tshwj xeeb rau ib qho G protein.
Dab tsi yog qhov zoo sib xws ntawm GAP thiab GEF?
- GAP thiab GEF yog ob yam uas tuaj yeem tswj hwm txoj haujlwm ntawm G protein.
- Ob yam yog cov proteins.
- Cov khoom no khi rau G proteins lossis GTPases.
- Ob qho tib si tuaj yeem tswj cov kab hluav taws xob qis qis
- Lawv lub luag haujlwm tseem ceeb heev rau kev ua haujlwm ntawm tes.
Qhov txawv ntawm GAP thiab GEF yog dab tsi?
GAP yog cov protein uas tuaj yeem tua cov kab hluav taws xob qis ntawm lub xov tooj tom qab khi rau G protein thaum GEF yog cov protein uas tuaj yeem tig rau qis qis qis ntawm cov cell tom qab khi rau G protein. Yog li, qhov no yog qhov sib txawv tseem ceeb ntawm GAP thiab GEF. Tsis tas li ntawd, GAP txhim kho GTP hydrolysis cov tshuaj tiv thaiv ntawm G protein, thaum GEF txhim kho qhov kev sib cais ntawm GDP los ntawm G protein.
Cov hauv qab no qhia txog qhov sib txawv ntawm GAP thiab GEF hauv daim ntawv teev npe rau ib sab ntawm kev sib piv.
Summary – GAP vs GEF
GAP thiab GEF yog ob yam uas tuaj yeem tswj hwm qhov chaw qis qis ntawm lub xov tooj ntawm tes tom qab khi rau G proteins. GAP yog cov protein uas tuaj yeem tua cov teeb liab hauv qab ntawm lub xov tooj tom qab khi rau G protein, thaum GEF yog cov protein uas tuaj yeem tig rau qis qis ntawm lub xov tooj tom qab khi rau G protein. Yog li, qhov no yog cov ntsiab lus ntawm qhov sib txawv ntawm GAP thiab GEF.
