QuestionSBA
QuestionChoice
This is one of the functions of the Ga-13 subunits which bind to the guanine nucleotide exchange factors for Rho GTPases. This activates their modulatory action on the actin cytoskeleton to alter cell conformation.
10001104
d
Modulates the cytoskeleton
QuestionChoice
This is one of the functions of the beta-gamma subunit: they promote the opening of inward-rectifying potassium channels, thus hyper-polarising cells. These subunits can also modulate the activity of calcium channels and the Ras-Raf mitogenic signalling pathway.

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10001105
e
Opens potassium channels
QuestionChoice
This is the function of Ga-s which increases the generation of cAMP. This activates PKA which phosphorylates intracellular targets to modulate cell activity.
10001102
b
Activates adenylyl cyclase
QuestionChoice
This is the function of Ga-q which increases the generation of diacylglycerol. This activates PKC which phosphorylates intracellular targets to modulate cell activity and inositol trisphosphate, which binds to IP3 receptors. This allows for calcium efflux from the endoplasmic reticulum into the cytoplasm to modulate cell activity.
10001101
a
Activates phospholipase C
QuestionChoice
This is the function of Ga-i/o subunits. This reduces the generation of cAMP which reduces the activity of PKA and subsequently reduces the phosphorylation of intracellular targets to modulate cell activity.
10001103
c
Inactivates adenylyl cyclase
Concept
Chapter
2693
3884
Cell signalling
Topic
181
Structure and Function of Cells
12767
Upon activation, the Ga-q subunit of a G-protein does what?
a