MEMBRANE TRANSPORT

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??? ????

• MEMBRANE TRANSPORT

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????

• ????????
• ??????
• ??????
• ??? ????
• ?????
• ??????
• ?????

??ABC ??? ?????? ????????????? ?????? ?????? ?????
? ?????? ????????
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• ?????????????????????????1530,??????????????????
  ????2/3?
• ????????
• ??????????????????
• ????????????,??????????

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Membrane Transport Proteins
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??? ????
6
??????

• ??????(free diffusion)
• ??????(??????)??
• ????????
• ?????????
• ???PKD/t , K?????, D?????,t??????

7
(No Transcript)
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• ????????????
• ??????????
• ??????????
• ????????????
• ??????????????????
• ??????????,???????????

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??????

• ??????(facilitated diffusion)?
• ?? ?????? ???????????????? ?????????
• ????????????

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(?)????(ionophore)

• ??????,???????????????????????

• ???????K DNP?FCCP???H?????A23187???????

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• ????A,15????????,2?????????,???????????H?Na?K??
  ??????

Gramicidin A an antibiotic that acts as an ion
pore.
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(?)????(channel protein)

• ???????,?????????????,???????
• ????????,??????
• ????????????,??????????,?????(????????????????????
  ?????)?

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Ion Channels
----or----
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1??????(ligand gated channel)

• ?????????????,????????, ???,??????????
• ???????,?????????????,??-???????
• Ach???4????(a2ß?d)???

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Nicotinic acetylcholine receptor
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Three conformation of the acetylcholine receptor
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2??????(voltage gated channel)

• ??????????????,????
• ?????,??????6??
• Na?K?Ca2?????????,?????????????

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Voltage gated K channel
K?????????,?????6???a??(S1-S6)
,N?C??????????S5-S6?????ß?? (P??H5?),??????,????K
???????S4???????
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K channel
4th subunit not shown
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Ion-channel linked receptors in neurotransmission
???????Ach??????????????,???????????Na???K??????
,??????????? Ca2????,Ca2?????,???????
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3????????

• CNG????????????????C????,???????????
• ????????????
• ?????????????G?????????,????????,??cAMP,??cAMP????
  ???,???????,????,??????,??????????

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4??????

• ?????????????????????
• ???????????????,???????,?2??1???????,?Na?K?Ca2,
  ?Ca2??,????????????????????? ,??????????????

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5????

• 1991?Agre??????????CHIP28 (28 KD
  ),CHIP28?mRNA???????????????,????????????Hg2???
• ?????????????11?????,?????????(Aquaporin,AQP)?

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2003?,??????????????????,??????????,????????????
????????
Peter Agre
Roderick MacKinnon
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??? ????

• ??
• ??????(?????)??
• ?????
• ????????
• ????
• ?????????????
• ? ATP????????ATP????
• ??????????????,?????

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?????

• ???2?????2???????4??,??Na-KATP?,???????????
• ????
• ????????????????,????P-type??????????3????,2?????

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Na-KATP PUMP
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Na-KATP pump can catalyze the formation of ATP
under laboratory condition
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• ??????
• ?????????,??????
• ????Na?K??????
• ???????????
• ????????????????Mg2??????????????

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??????

• ???????????????(?????10-7M,??10-3M)?
• ??????????
• ??
• P????,?????ATP??,??2?Ca2?????????????????????90?
  
• ?????(Na-Ca2 exchanger),??????????,?????????????

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Ca ATPase
Maintains low cytosolic Ca Present In Plasma
and ER membranes
Model for mode of action for Ca ATPase
Conformation change
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?????

• 1?P-type????????H??????????H-K?(????)?
• 2?V-type?????????,??ATP????,????????,????????????
  ?????
• 3?F-type?????????ATP,?ATP??,???????????????????

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Four types of ATP-powered pumps
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??ABC ???(ABC transporter)

• ???????,?????????,?????????ATP???(ATP binding
  cassette),???
• ??ABC?????????????,??????????????????????????????
  ??????????????

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Mammalian MDR1 protein
ABC????????????????MDR (multidrug resistance
protein )????????????ABC???,???????,?40??????????
?????
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??????cotransport

• ???????????????????????????????
• ????????????Na????????
• ??????????H????????
• ??????(symport)?????(antiport)?

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• 1?????(symport)
• ???????????????Na?????????????????H????
• 2?????(antiport)
• ?Na???Cl--HCO3-??,?Na?HCO3-??????Cl-?H???,?????
  ??????3???

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Glucose is absorbed by symport
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??? ?????????

• ??????????(endocytosis)?????(exocytosis)??????????
  ???????
• ?????????,???????

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??????

• ?????????????,??????????

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• ??????

• ???????????????

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• ??????

exocytosis

• ??????????????,????,??????????

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• ??????
• ?????????????????,???????????????????????????????
  ???
• ????????
• ?????????????????????????????????????????????????