Binding of NOTCH3 to YBX1 (YB-1) triggers cleavage of NOTCH3 by the gamma-secretase complex. The exact steps of YBX1-mediated NOTCH3 activation are not known. The gamma-secretase complex releases NOTCH3 intracellular domain (NICD3), leading to activation of NOTCH3 target genes downstream of YBX1 (Rauen et al. 2009).
aspartic-type endopeptidase activity of gamma-secretase complex [plasma membrane]