Disease relevance of RTKN

• By analyzing the Stanford Microarray Database for the expression profiles of gastric tissues, we also found a progressional increase in RTKN expression in nonneoplastic mucosa, GC, and then lymph node metastases (p < 0.005 by Jonckheere-Terpstra test), suggesting that RTKN expression correlates with GC progression [1].
• In neuroblastoma Neuro2a cells, Rhotekin and Sept9b were enriched in the tip of neurites, a location where cortical actin reorganization is induced upon stimulation with lysophosphatidic acid [2].
• Overexpression of rho effector rhotekin confers increased survival in gastric adenocarcinoma [1].
• While investigating how hypoxia could activate this signaling pathway, using the GST-Rhotekin RBD pulldown assay, we showed the early activation of RhoB by reactive oxygen species under hypoxic conditions and, subsequently, its participation in the ensuing cellular adaptation to hypoxia [3].
• The C terminus of the B5 receptor for herpes simplex virus contains a functional region important for infection [4].

High impact information on RTKN

• Repeated vaccination provided significantly higher B5-specific and thus EEV-neutralizing antibody responses [5].
• Using the Rhotekin binding assay to assess RhoA activation, we observed that engagement of alpha6beta4 by either antibody-mediated clustering or laminin attachment resulted in a two- to threefold increase in RhoA activation, compared with cells maintained in suspension or plated on collagen [6].
• The center region of Rhotekin was sufficient for the septin reorganization in the cells, and likely to interact indirectly with the C-terminal half of a septin Sept9b, where a GTPase domain is located [2].
• Reporter gene assays and electrophoretic mobility shift assay confirmed that RTKN overexpression led to constitutive activation of NF-kappaB through the phosphorylation of IkappaB by IKKbeta [7].
• Conversely, reducing RTKN expression by small interfering RNAs greatly sensitized cells to apoptosis [7].

Biological context of RTKN

• Compared with BAC clone AC005041 sequence, there were 12 exons for the RTKN gene and it spanned a 16.5-kb genomic region [8].
• In addition, the RTKN gene was localized to chromosome 2p13 between markers D2S145 at 6.94 cR (LOD > 12) and D2S286 at 8.12 cR (LOD > 9.7) by radiation hybrid panel mapping [8].
• After the optimal reverse-transcription polymerase chain reaction condition was established, the mRNA expression levels of the RTKN gene in the lesions and tumor-free bladder tissues were examined semiquantitatively, and the relationships between expression levels of RTKN and clinical pathological features were analyzed [9].
• To explore the mechanisms underlying RTKN-mediated cell survival, a reporter assay was performed [1].
• The role of RTKN in the pathogenic development of GC was investigated by transfection and expression of RTKN in AGS gastric cells, which express endogenous RTKN at a low basal level [1].

Anatomical context of RTKN

• In this study, we further showed that RTKN is expressed at a low level in normal cells and is overexpressed in many cancer-derived cell lines [7].
• Northern analysis using human multiple tissue blots showed that RTKN is predominantly expressed in the kidney and spinal cord, and, to a lesser degree, in the thyroid, tongue, liver, brain, prostate, trachea, and stomach [1].
• Accordingly, we used the Rhotekin binding assay to assess RhoA activation in intestinal epithelial cells and observed that RhoA was activated by leukotriene D4 (LTD4) [10].
• Next, we used a rhotekin pulldown assay to confirm directly that IL-1beta deactivates Rho, and further demonstrated that a constitutively active Rho construct rescued astrocytes from developing an IL-1beta-induced reactive phenotype [11].

Associations of RTKN with chemical compounds

• Consistent with these data, RTKN-expressing cells showed increased chemoresistance to 5-fluorouracil and paclitaxol, and the resistance was greatly attenuated by NF-kappaB inhibitor [7].
• The RTKN-mediated antiapoptotic effect was blocked by the nuclear factor-kappaB (NF-kappaB) inhibitors, curcumin or parthenolide, but not by the phosphatidylinositol 3'-OH-kinase inhibitor, LY294002, or the MAP kinase inhibitor, PD98059 [7].
• Our results showed that overexpression of RTKN induced robust activation of NF-kappaB, and RTKN-mediated NF-kappaB activation was suppressed significantly by C3 transferase, an inhibitor of the small GTPase Rho [1].
• Bovine trachea challenged with a half-maximally effective concentration of carbachol (CCh) was flash-frozen at different times, then assayed for Rho (rhotekin pull-down assay) and ROCK (Western blot; radiometric assay) activities [12].

Regulatory relationships of RTKN

• The interaction of PIST with beta-catenin was inhibited by the presence of Rhotekin [13].

Other interactions of RTKN

• Similarly, RhoA activity, as measured by the Rhotekin binding assay, was elevated in the PC-3 highly invasive cells [14].
• The effect of TGF-beta on Rho-GTPase activity was assessed by GST-rhotekin binding domain pulldown assay and detected by Western blot analysis [15].
• We then demonstrated that Rhotekin and PIST are expressed in developmental stage-specific manners in the rat brain [13].
• Using pull-down assays with recombinant rhotekin or p21-activated kinase, we demonstrated the activation of RhoGTPases by PMT in DCs [16].

Analytical, diagnostic and therapeutic context of RTKN

• RT-PCR analysis confirmed that RTKN was overexpressed in most (5/7; 71%) GC examined [1].
• The activity of the proteins was studied by membrane release assay, rhotekin pulldown experiments, and microinjection [17].
• In immunofluorescence analyses, Rhotekin and PIST were suggested to co-localize at synapses in rat primary cultured hippocampal neurons [13].

References