Gene Expression Profiling in Cells with Enhanced ?-Secretase Activity

Magold, Alexandra I.; Cacquevel, Matthias; Fraering, Patrick C.

Functional clustering of the microarray data revealed the overrepresentation of the ''receptor binding'' cluster, which includes four different Wnt signaling molecules and b-catenin. b-Catenin also finds itself in the center of interactions of proteins encoded by strongly differentially expressed genes. Components downstream of the canonical Wnt pathway, like c-myc, c-jun and cycD, influence the cell cycle, the latter as mentioned is downregulated by protein tyrosine phosphatase receptor type c (Ptprg). Interestingly, we found PTPRG transcription to be strongly decreased in cells with enhanced c-secretase. Barnea et al. [51] identified a subfamily of PTPRs, defined by the carbonic anhydrase-like domain in the extracellular region of PTPRG, and described its expression during hippocampal formation, and in septal and midline thalamic nuclei in the cortex of newborn rats (in contrast to the expression pattern in adult rats, which is reduced to the hippocampal formation). Several groups have shown a connection between alterations in receptor tyrosine phosphatases' expression levels and c-secretase [52, 53] . However, we report here for the first time, to our knowledge, the transcriptional connection between the receptor tyrosine phosphatase type gamma and c-secretase.