Which of the following events is an example of negative feed

Which of the following events is an example of negative feedback in a signaling pathway ?

A Binding of the beta/gamma subunits to an alpha subunit of a heterotrimeric GTPase.

B Binding of ORAI to STIM1.

C Binding of a GEF to a monomeric GTPase.

D Binding of a GDP-bound heterotrimeric GTPase to adenylyl cyclase.

E Calcium-calmodulin mediated activation of a membrane localized Ca2+ pump that moves Ca2+ out of the cytoplasm.

Solution

The correct answer is:

E.Calcium-calmodulin mediated activation of a membrane localized Ca2+ pump that moves Ca2+ out of the cytoplasm.

Reason:The above statement is a negative feed back example in signalling pathway as increase in levels of calcium ions out of cytoplasm leads to deactivation of Ca2+ pump.