gamma-Cleavage is dependent on zeta-cleavage during the proteolytic processing of amyloid precursor protein within its transmembrane domain.The Journal of biological chemistry (2005)
Abstractbeta-Amyloid precursor protein apparently undergoes at least three major cleavages, gamma-, epsilon-, and the newly identified zeta-cleavage, within its transmembrane domain to produce secreted beta-amyloid protein (Abeta). However, the roles of epsilon- and zeta-cleavages in the formation of secreted Abeta and the relationship among these three cleavages, namely epsilon-, zeta-, and gamma-cleavages, remain elusive. We investigated these issues by attempting to determine the formation and turnover of the intermediate products generated by these cleavages, in the presence or absence of known gamma-secretase inhibitors. By using a differential inhibition strategy, our data demonstrate that Abeta(46) is an intermediate precursor of secreted Abeta. Our co-immunoprecipitation data also reveal that, as an intermediate, Abeta(46) is tightly associated with presenilin in intact cells. Furthermore, we identified a long Abeta species that is most likely the long sought after intermediate product, Abeta(49), generated by epsilon-cleavage, and this Abeta(49) is further processed by zeta- and gamma-cleavages to generate Abeta(46) and ultimately the secreted Abeta(40/42). More interestingly, our data demonstrate that gamma-cleavage not only occurs last but also depends on zeta-cleavage occurring prior to it, indicating that zeta-cleavage is crucial for the formation of secreted Abeta. Thus, we conclude that the C terminus of secreted Abeta is most likely generated by a series of sequential cleavages, namely first epsilon-cleavage which is then followed by zeta- and gamma-cleavages, and that Abeta(46) produced by zeta-cleavage is the precursor of secreted Abeta(40/42).
Publication DateNovember 11, 2005
Citation InformationGuojun Zhao, Mei-Zhen Cui, Guozhang Mao, Jianxin Tan, et al.. "gamma-Cleavage is dependent on zeta-cleavage during the proteolytic processing of amyloid precursor protein within its transmembrane domain." The Journal of biological chemistry Vol. 280 Iss. 45 (2005)
Available at: http://works.bepress.com/xuemin_xu/13/