THE CELL
CELL COMMUNICATION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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transfer a phosphate group from a kinase to the next relay molecule in a series
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inactivate protein kinases to turn off signal transduction
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amplify signal transduction so it activates multiple relay molecules
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amplify the second messenger cAMP
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Detailed explanation-1: -Abstract. Protein phosphatases have recently been identified that inactivate MAP kinases and turn off intracellular signalling pathways. Their regulation may determine the response of cells to stimuli that signal via MAP kinases.
Detailed explanation-2: -Protein phosphatases can operate as both immediate and delayed regulators of signal transduction, capable of attenuating or amplifying signalling.
Detailed explanation-3: -Protein kinases and phosphatases are enzymes catalysing the transfer of phosphate between their substrates. A protein kinase catalyses the transfer of -phosphate from ATP (or GTP) to its protein substrates while a protein phosphatase catalyses the transfer of the phosphate from a phosphoprotein to a water molecule.
Detailed explanation-4: -Protein phosphatases are enzymes that can rapidly remove phosphate groups from proteins (dephosphorylation) and thus inactivate protein kinases. Protein phosphatases are the “off switch” in the signal transduction pathway.
Detailed explanation-5: -A phosphatase is an enzyme that removes a phosphate group from a protein. Together, these two families of enzymes act to modulate the activities of the proteins in a cell, often in response to external stimuli.