Qhov sib txawv tseem ceeb ntawm kev tsis muaj zog thiab kev sib tw treadmilling yog qhov tsis muaj zog dynamic tshwm sim thaum microtubules sib sau ua ke thiab sib cais ntawm ib qho kawg, thaum treadmilling tshwm sim thaum ib kawg polymerizes, thiab lwm qhov kawg dissembles.
Microtubules yog dynamic cellular polymers. Lawv tswj hwm ntau cov haujlwm ntawm tes uas tseem ceeb rau tib neeg lub cev. Lawv yog cell division, mitosis, adhesion, qhia migrations, cell signaling, vesicle thiab protein xa rov qab los ntawm lub plasma daim nyias nyias, polymerization, thiab remodeling cellular lub koom haum thiab cell zoo. Lub cytoskeleton muaj microtubules, nruab nrab filaments, thiab actin filaments. Lawv remake los yog reorganize lawv tus kheej nyob rau hauv teb rau sab nraud teeb liab uas tswj cov kev ua ntawm tes. Dynamic instability thiab treadmilling yog ob qhov tshwm sim tshwm sim hauv ntau lub cellular cytoskeletal filaments.
Dynamic Instability yog dab tsi?
Dynamic instability tso cai rau cov hlwb rov tsim kho cytoskeleton sai sai thaum xav tau. Microtubules muaj cov yam ntxwv tshwj xeeb dynamic. Feem ntau, ib feem ntawm microtubules loj hlob sai thaum lwm tus me me. Qhov kev sib xyaw ua ke ntawm kev poob qis, kev loj hlob, thiab kev hloov pauv sai ntawm ob lub xeev yog hu ua dynamic instability. Dynamic microtubules muaj lub neej ntev, yog li cov pob khoom ntawm microtubules nyob rau hauv cov txheej txheem ua si. Cov txheej txheem loj hlob thiab shrinkage ntawm microtubules yog cov txheej txheem nquag thiab siv zog. Qhov no ua rau microtubules yoog sai rau kev hloov ib puag ncig. Qhov no kuj tso cai rau lawv los ua cov txheej txheem hauv kev teb rau cov kev xav tau ntawm tes.
Daim duab 01: Dynamic Instability
Microtubules yog tsim los ntawm cov protein tubulin subunits khi rau guanosine triphosphate (GTP), uas yog lub zog nqa. Cov hlwb siv lub zog kom tswj tau qhov siab GTP-tubulin concentration rau polymerization. Cov txheej txheem no nrawm nrawm nrog qhov kawg ntawm microtubules thiab pab txhawb kev loj hlob ntawm microtubules. Tom qab kev koom ua ke ntawm subunits rau hauv microtubules, GTP hydrolyzes rau guanosine diphosphate (GDP), tso lub zog. GDP-tubulin tsis curl sab nraud thaum dai hauv microtubules. Microtubules loj hlob thaum qhov kawg ruaj khov. Txawm li cas los xij, thaum xaus pib sib cais, kev nthuav dav yuav tshwm sim. Qhov no ua rau lub zog tso tawm hauv tubulin subunits li microtubules sai sai.
Treadmilling yog dab tsi?
Treadmilling tshwm sim hauv ntau lub cellular cytoskeleton filaments, tshwj xeeb tshaj yog nyob rau hauv actin filaments thiab microtubules. Qhov no tshwm sim thaum qhov ntev ntawm ib qho filament loj hlob thaum lwm qhov kawg shrinks. Qhov no ua rau ib ntu filament uas txav mus thoob plaws cytosol lossis stratum. Qhov ntawd kuj yog vim kev tshem tawm cov protein subunits tas li los ntawm cov filaments ntawm ib kawg thaum cov protein subunits ntxiv los ntawm lwm qhov kawg. Ob qhov kawg ntawm actin filament txawv ntawm qhov sib ntxiv thiab tshem tawm cov subunits. Qhov ntxiv xaus nrog kev nrawm nrawm yog hu ua barbed xaus, thiab cov minus xaus nrog qeeb zog yog hu ua pointed xaus. Elongation ntawm actin filaments tshwm sim thaum G-actin (dawb actin) khi rau ATP. Feem ntau, qhov kawg zoo yog txuam nrog G-actin. Kev khi ntawm G-actin rau hauv F-actin tshwm sim nrog kev tswj hwm ntawm qhov tseem ceeb.
Daim duab 02: Actin Treadmilling
Critical concentration yog qhov concentration ntawm G-actin lossis microtubules uas nyob ntawm tus nqi sib npaug yam tsis muaj kev loj hlob lossis kev poob qis. Actin polymerization ntxiv tswj cov profilein thiab cofilin. Profilin yog ib qho actin-binding protein koom nrog hauv kev hloov pauv hloov pauv thiab rov tsim kho ntawm actin. Cofilin yog ib tsev neeg actin-binding ntawm cov proteins uas cuam tshuam nrog kev depolymerization sai ntawm actin microfilaments. Treadmilling ntawm microtubules tshwm sim thaum ib kawg polymerizes thaum lwm qhov disassembles.
Dab tsi yog qhov zoo sib xws ntawm Dynamic Instability thiab Treadmilling?
- Dynamic instability thiab treadmilling yog tus cwj pwm hauv cytoskeletal polymers.
- Lawv tshwm sim hauv microtubules.
- Ntxiv mus, ob qho tib si cuam tshuam nrog nucleoside triphosphate hydrolysis.
- Lawv koom nrog kev loj hlob thiab txo qis ntawm filaments.
- Ob leeg yog cov txheej txheem nquag.
- Ntxiv mus, lawv xav tau lub zog.
Qhov txawv ntawm Dynamic Instability thiab Treadmilling yog dab tsi?
Dynamic instability tshwm sim nyob rau hauv microtubules thiab lawv sib sau ua ke thiab disassemble ntawm ib kawg. Lub caij no, treadmilling tshwm sim hauv actin filaments thiab microtubules. Yog li, qhov no yog qhov sib txawv tseem ceeb ntawm dynamic instability thiab treadmilling. Ntxiv mus, cov protein tseem ceeb koom nrog hauv kev tsis sib haum xeeb yog tubulin thaum nyob hauv treadmilling, nws yog actin. Tsis tas li ntawd, GTP-bound nucleotides feem ntau muab lub zog rau cov txheej txheem tsis ruaj khov. Qhov twg, ATP muab lub zog rau treadmilling.
Cov hauv qab no qhia txog qhov sib txawv ntawm qhov tsis muaj zog tsis ruaj khov thiab treadmilling hauv daim ntawv tabular rau ib sab ntawm kev sib piv.
Summary – Dynamic Instability vs Treadmilling
Dynamic instability tshwm sim nyob rau hauv microtubules thiab lawv sib sau ua ke thiab dissemble ntawm ib kawg. Treadmilling tshwm sim hauv actin filaments thiab microtubules. Dynamic instability tso cai rau cov hlwb los kho cov cytoskeleton sai sai thaum xav tau. Treadmilling tshwm sim nyob rau hauv ntau cellular cytoskeleton filaments. Ib qho me me ntawm microtubules loj hlob sai thaum lwm tus me me; Yog li ntawd, ib qho kev hloov pauv sai sai tshwm sim thaum lub sij hawm dynamic instability. Thaum lub sij hawm treadmilling, qhov ntev ntawm ib lub filament elongates thaum lwm kawg shrinks. Yog li, qhov no qhia txog qhov sib txawv ntawm qhov tsis ruaj khov thiab treadmilling.
