Gap Junction vs Tight Junction
Cell junctions yog qhov chaw tshwj xeeb ntawm cov cell membrane nrog cov haujlwm tshwj xeeb thiab pom muaj nyob hauv ntau cov kab mob. Muaj peb hom kev sib txuas ntawm tes; uas yog, nruj junctions, qhov sib txawv junctions, thiab adhering (anchoring) junctions. Cov junctions no yog ib qho tseem ceeb los tswj kev sib txuas lus ntawm tes-rau-cell, pab txhawb kev thauj mus los ntawm cov hlwb, ua kom tsis muaj ciam teb txhawm rau tiv thaiv kev sib kis, thiab tuav cov hlwb ua ke los ntawm kev khi lawv nruj thiab lwm yam.
Tight Junctions
Tight junctions yog tus cwj pwm los ntawm fusion ntawm cov cell membranes uas nyob ib sab thiab tsuas pom muaj nyob rau hauv cov ntaub so ntswg epithelial. Tight junctions muaj ntau lub luag haujlwm suav nrog, kaw qhov chaw intercellular hauv epithelial thiab endothelial cell khaubncaws sab nraud povtseg thiab tiv thaiv dawb paracellular passage ntawm cov khoom. Tsis tas li ntawd, cov junctions no txiav txim siab qhov polarity ntawm cov hlwb epithelial los ntawm kev tsim ib thaj tsam ntawm apical domain ntawm plasma membrane thiab basolateral domain thiab tiv thaiv kev sib kis ntawm cov protein thiab lipid ntawm cov hlwb. Lub permeability ntawm nruj junctions nyob ntawm seb lub molecule tus nqi thiab cov duab. Tsis tas li ntawd, nyob ntawm qhov chaw ntawm kev sib tshuam nruj, qhov permeability rau ions thiab dej-soluble molecules ntawm qhov hnyav molecular sib txawv. Lub barrier khoom ntawm nruj junction yog txiav txim los ntawm tus naj npawb ntawm parallel nruj junction strands. Cov strands yog tsim los ntawm aggregating claudin thiab occluding proteins, thiab txuam zonula proteins.
Gap Junctions
Gap junctions yog lub luag haujlwm los muab kev sib txuas lus ntawm tes rau ntawm tes los ntawm kev thauj cov ions thiab cov khoom me me mus txog kwv yees li 1 kDa. Tsis tas li ntawd, lawv tso cai rau cov tshuaj lom neeg thiab hluav taws xob sib txuas ntawm cov hlwb uas nyob ib sab uas xav tau rau lub plawv thiab cov nqaij mos ntawm tes ua haujlwm thiab tsis tu ncua embryogenesis. Gap junction nyob rau hauv cov nqaij du yog hu ua ib tug nexus thaum, nyob rau hauv lub plawv cov leeg, nws pab ua ib feem ntawm intercalated disc. Gap junctions yog tsim los ntawm ib qho membrane proteins hu ua connexins. Rau connexins sib sau ua ke los tsim ib qho qauv hu ua connexon. Cov connexons no ua ke nrog cov connexons nyob ib sab ntawm cov cell membranes nyob sib ze los tsim cov kab dej hydrophilic.
Qhov txawv ntawm Gap Junctions thiab Tight Junctions yog dab tsi?
• Tsis zoo li qhov sib txawv junctions, nruj junctions pom tsuas yog nyob rau hauv lub epithelial hlwb. Gap junctions tau nthuav dav hauv kev faib tawm.
• Tight junctions ua teeb meem thiab tiv thaiv los yog txo cov kev thauj mus los ntawm cov khoom nyob rau hauv lub extracellular chaw nruab nrab ntawm cov hlwb thaum sib txawv junctions ua passages uas tso cai rau dhau molecules ntawm cell.
• Ntawm qhov sib txawv junctions, muaj kwv yees li 2nm qhov sib txawv ntawm cov hlwb uas nyob ib sab. Ntawm kev sib tshuam nruj, tsis muaj qhov sib txawv ntawm cov hlwb uas nyob ib sab.
• Tsis zoo li qhov sib txawv ntawm qhov sib txawv, cov junctions nruj tswj cov cell polarity ntawm cov protein complexes (CRB3 thiab Par3 complexes).
• Tight junctions yog pom nyob rau hauv ib tug electron microscope raws li nruam, anastomosing strands ntawm hais, tsim bands los yog complex network, thaum sib txawv junctions yog pom raws li aggregated hais nyob rau hauv tej chaw los yog loj cheeb tsam.
• Gap junctions muaj connexin proteins thaum, nruj junctions muaj aggregation ntawm claudin thiab occluding proteins, thiab txuam zonula proteins.
