A Comparison of NSP-Reticulons With Conventional Neuroendocrine Markers in Immunophenotyping of Lung Cancers

A novel protein, RTN-xS, interacts with both Bcl-xL and Bcl-2 on endoplasmic reticulum and reduces their anti-apoptotic activity

“…When transiently transfected D98/AH2 cells were biochemically fractionated, both RTN-x S and NSP-C were mainly recovered in the microsomal fraction, with (Figure 5a), similarly to the previous immunohistochemical studies on reticulons including NSP-C (Senden et al, 1996;GrandPre et al, 2000). These results indicate that RTN-x S is mainly localized to the ER.…”

“…Because reticulon family members including NSP-C are known to be localized on the ER (Senden et al, 1996;GrandPre et al, 2000), the subcellular localization of RTN-x S was examined by the two di erent methods; biochemical fractionation and immunocytochemistry. When transiently transfected D98/AH2 cells were biochemically fractionated, both RTN-x S and NSP-C were mainly recovered in the microsomal fraction, with (Figure 5a), similarly to the previous immunohistochemical studies on reticulons including NSP-C (Senden et al, 1996;GrandPre et al, 2000).…”

“…Immunohistochemical studies have revealed that RTN proteins are anchored to the ER (Senden et al, 1996;GrandPre et al, 2000) probably through two putative transmembrane domains in the homologous C-terminal region, so these proteins were renamed the reticulon (RTN) family (Roebroek et al, 1998). Little is known about the function of the RTN family in apoptosis.…”

Do cancer cells die because of Nogo-B?

“…RT-PCR and Western blot clearly demonstrate the presence of endogenous Nogo-B (Figure 1a, b). Immunocytochemistry ( Figure 1c) revealed a typical subcellular localization of endogenous Nogo-B protein in an ER-like pattern in SaOS-2 cells, as has been widely described for other reticulon proteins (Senden et al, 1994;van de Velde et al, 1994a;Morris et al, 1999). To analyse if there are any differences in the 'proapoptotic' domain of Nogo-B expressed by SaOS-2 cells because of mutations of the nogo gene, we cloned a 0.8 kb fragment of the Nogo-B transcript comprising the 'proapoptotic' domain in the C-terminus.…”

“…In addition, there are a series of studies carried out by the group of Ramaekers and Van de Ven illustrating that the first member of the reticulon family, RTN1, is highly expressed in SCLCs and non-SCLCs. Thus, RTN1 has been suggested as a marker for these tumours (van de Velde et al, 1994b;Senden et al, 1996Senden et al, , 1997a. The work of Tagami et al (2000) showed an association and partial colocalization of Nogo-B (Rtn-x S ) with Bcl-2 and Bcl-x L .…”