Role of PKM-zeta in Long-Lasting Long-Term Potentiation

(a) The messenger RNA for PKM-zeta is constantly transcribed from DNA in the nucleus and transported to dendritic spines. However, the action of the enzyme Pin1 blocks the translation of the mRNA into the PKM-zeta protein. (b) When the conditions for LTP are met, Ca2+ ions enter the spine and activate several enzymes, including CAM-KII. This enzyme then suppresses the action of Pin1, which permits PKM-zeta mRNA to direct the production of the PKM-zeta protein, which activates the enzyme NSF. Activated NSF initiates the movement of AMPA receptors into the dendritic spine, as was shown in Figure 13.11. (c) PKM-zeta not only activates NSF; it suppresses Pin1 and thus insures that molecules of PKM-zeta protein continue to be produced.