06-1020 Sigma-AldrichAnti-NET31 Antibody

Therapeutic targets for more effective and less toxic treatments of lung cancer remain important. Here we report the identification of the integral nuclear envelope protein TMEM209 as a critical driver of human lung cancer growth and survival. TMEM209 expression was normally limited to testis, but we found that it was widely expressed in lung cancer, in which it localized to the nuclear envelope, Golgi apparatus, and the cytoplasm of lung cancer cells. Ectopic overexpression of TMEM209 promoted cell growth, whereas TMEM209 attenuation was sufficient to block growth. Mass spectrometric analysis identified the nucleoporin protein NUP205 as a TMEM209-interacting protein, stabilizing NUP205 and increasing the level of c-Myc in the nucleus. Taken together, our findings indicate that TMEM209 overexpression and TMEM209-NUP205 interaction are critical drivers of lung cancer proliferation, suggesting a promising new target for lung cancer therapy.

A favored hypothesis to explain the pathology underlying nuclear envelopathies is that mutations in nuclear envelope proteins alter genome/chromatin organization and thus gene expression. To identify nuclear envelope proteins that play roles in genome organization, we analyzed nuclear envelopes from resting and phytohemagglutinin-activated leukocytes because leukocytes have a particularly high density of peripheral chromatin that undergoes significant reorganization upon such activation. Thus, nuclear envelopes were isolated from leukocytes in the two states and analyzed by multidimensional protein identification technology using an approach that used expected contaminating membranes as subtractive fractions. A total of 3351 proteins were identified between both nuclear envelope data sets among which were 87 putative nuclear envelope transmembrane proteins (NETs) that were not identified in a previous proteomics analysis of liver nuclear envelopes. Nuclear envelope localization was confirmed for 11 new NETs using tagged fusion proteins and antibodies on spleen cryosections. 27% of the new proteins identified were unique to one or the other of the two leukocyte states. Differences in expression between activated and resting leukocytes were confirmed for some NETs by RT-PCR, and most of these proteins appear to only be expressed in certain types of blood cells. Several known proteins identified in both data sets have functions in chromatin organization and gene regulation. To test whether the novel NETs identified might include those that also regulate chromatin, nine were run through two screens for different chromatin effects. One screen found two NETs that can recruit a specific gene locus to the nuclear periphery, and the second found a different NET that promotes chromatin condensation. The variation in the protein milieu with pharmacological activation of the same cell population and consequences for gene regulation suggest that the nuclear envelope is a complex regulatory system with significant influences on genome organization.