GPCR 2 Flashcards
EFFECTORS OF TRIMERIC G PROTEINS INCLUDE…………… THAT CREATE ……………………….. AND ION CHANNLES WHOSE GATING IS REGULATED EITHER DIRECTLY (…………… SUBUNITS) OR INDIRECTLY BY SECOND MESSENGERS AND THEIR EFFECTORS
ENZYMES
2ND MESSENGERS
BETA -GAMMA
DESCRIBE WHAT HAPPENS IN THE GS PATHWAYS
- ADRENALINE BINDS TO GPRC
- CONFORMATIONAL CHANGE LEADS TO ACTIVATION OF G PROTEIN
- ALPHA SUBUNIT ACTIVATES ADENYLATE CYCLASE TO PRODUCE CAMP THAT CAN ACTIVATE PKA THAT CAN ACTIVATE CALMODULIN WHICH IS CONVERTED TO CA-CM TO MAKE ACTIVE GLUCOSE 6P
IN WHAT WAYS CAN PATHWAYS LIKE GS PATHWAY BE LIMITED
- INHERENT GTPASE ACTION OF THE ALPHA SUBUNIT CAN STOP THE PROCESS
- BAR UNDER LONG LASTING STIMULATION ACTS WITH THE BETA GAMMA UNIT TO CAUSE BETA ARRESTIN TO BIND AND BLOCK THE RECEPTOR
WHAT OTHER PATHWAYS CAN BE ACTIVATED FROM GPCR
SOME TRIMERIC C PROTEINS ACTIVATE PHOSPHOLIPASE C TO GENERATE IP3 AND DAG
SIGNALLING VIA LIPID DERIVED SECOND MESSENGERS IS SHARED ACROSS MANY RECEPTOR FAMILIES AND ALLOWS FOR
CROSS TALK
AMLPLIFICATION
GIVE THREE EXAMPLES OF MEMBRANE LIPIDS
- PIP2 (PHOSPHATIDYLINOSITOL 4,5 BISPHOSPHATE)
- PHOSPHATIDYLCHOLINE
- SPHINGOMYELIN
PIP2 IS BROKEN DOWN BY ………………… TO CREATE IP3 AND ……………
PHOPHOLIPASE C
DAG
PIP2 CAN BE BROKEN DOWN BY OTHER LIPID KINASES BUT WHAT WILL BE THE RESULT
BONDS WILL BE BROKEN IN DIFFERENT PLACES TO CREATE DIFFERENT BYPRODUCTS
USUALLY PHOSPHORYLATION ACTIVATES PROTEINS. WHAT ARE THE TWO EXCEPTIONS
GPCR
PLC BETA
WHERE DOES SPECIFICITY IN SIGNALLING COME FROM
SELECTIVE EXPRESSION AND CELLULAR LOCALISATION OF SIGNALLING MOLECULES
IE THERE ARE NUMEROUS ISOFORMS OF PLC AND PKC
WHAT DOES IP3 CAUSE RELEASE OF
CALCIUM IONS
WHAT DOES DAG CAUSE ACTIVATION OF
PROTEIN KINASE C
WHAT IS PROTEIN KINASE C
SER/THR KINASES ACTIVATED BY DAG (AND CA2+)
PLC BETA 1-4 ISOFORMS ARE REGULATED BY
THE GQ GPCR
WHAT ARE SOME THE FEATURES PHOSPHOLIPASE C BETA1-4
- PLEXTRIN HOMOLOGY ANCHOR AND RECOGNITION SITE FOR BETA-GAMMA SUBUNITS
- EF CALCIUM BINDING
- X AND Y THE LIPASE ACTIVE SITE
- C2 CALCIUM BINDING
- CT IS FOR Q SUBUNIT RECOGNITION
WHAT TEND TO BE THE FEATURES OF PKC
- C1 RECOGNITION SITE
- C2 CALCIUM BINDING PHOPHOLIPID BINDING
- KINASE DOMAIN
HOW DO YOU ACTIVATE PKC
WHEN DAG BINDS IT CAUSES DISSOCIATION OF AN INTRAMOLECULAR PSEUDO-SUBSTRATE DOMAIN FROM ITS ACTIVE SITE.
ACTIVATION OF GQPCR AND SYNTHESIS OF DAG IS NEWLY FOUND TO BE LINKED WITH
RECRUITMENT OF MUNC13 AND SECRETORY VESICLE DOCKING
PHOSPHOLIPID SYNTHESIS AND TURNOVER IS REGULATED BY MANY ENZYMES. MUTATIONS IN THE ENZYMES CAN BE DANGEROUS. GIVE AN EXAMPLE OF THIS.
MUTATION IN THE OCRL GENE ALTER PIP2 LEVELS GIVING RISE TO LOWE SYNDROME.
RENAL DYSFUNCTION
EYE DYSFUNCTION
BRAIN AND CNS ISSUES
IP3 GENERATED AT THE MEMBRANE CAN BIND WITH AN IP3 RECEPTOR WHERE
ON THE ER TO RELEASE CALCIUM IONS
WHAT ARE THE PROTEINS THAT SEQUESTER CALCIUM IONS IN THE ER
CALSEQUESTRIN
CALRETICULIN
WHAT KIND OF CHANNELS ARE RESPONSIBLE FOR STORE REFILLING
ORAI CHANNELS
THEY ARE GATED AND PHYSICALLY OPENED BY STIM LINK
