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Moesin is a member of the ezrin-radixin-moesin (ERM) family of proteins that are important for organizing membrane domains and receptor signaling and regulating the migration of effector T cells. Whether moesin plays any role during the generation of TGF-[beta]-induced Tregs (iTregs) is unknown. Here, we have discovered that moesin is translationally regulated by TGF-[beta] and is also required for optimal TGF-[beta] signaling that promotes efficient development of iTregs. Loss of moesin impaired the development and function of both peripherally derived iTregs and in vitro-induced Tregs. Mechanistically, we identified an interaction between moesin and TGF-[beta] receptor II (T[beta]RII) that allows moesin to control the surface abundance and stability of T[beta]RI and T[beta]RII. We also found that moesin is required for iTreg conversion in the tumor microenvironment, and the deletion of moesin from recipient mice supported the rapid expansion of adoptively transferred [CD8.sup.+] T cells against melanoma. Our study establishes moesin as an important regulator of the surface abundance and stability of T[beta]RII and identifies moesin's role in facilitating the efficient generation of iTregs. It also provides an advancement to our understanding about the role of the ERM proteins in regulating signal transduction pathways and suggests that modulation of moesin is a potential therapeutic target for Treg-related immune disorders., Introduction Moesin is a member of the ezrin-radixin-moesin (ERM) protein family, primarily expressed in the cytoplasm and concentrated in actin-rich cell surface structures. ERM proteins contain an aminoterminal FERM (4.1 [...]

The basis of constitutive activation of NF-[kappa]B, essential for survival and resistance to apoptosis in many tumors, is not well understood. We find that transforming growth factor [beta]2 (TGF [beta]2), predominantly in its latent form, is secreted by several different types of tumor cell lines that exhibit constitutively active NF-KB and that TGF [beta]2 potently stimulates the activation of NF-[kappa]B in reporter cells. Suppression of TGF [beta]2 expression by small interfering RNA kills prostate cancer PC3 cells, indicating that the TGF [beta]2-NF-[kappa]B pathway is important for their viability. These findings identify TGF[beta]2 as a potential target for therapeutic strategies to inhibit the growth of tumor cells that depend on constitutively active NF-[kappa]B, or to sensitize them to treatment with cytotoxic drugs. prostate cancer | small interfering RNA | ELISA | Smad

To isolate and characterize effector molecules of the transforming growth factor [Beta] (TGF[Beta]) signaling pathway we have used a genetic approach involving the generation of stable recessive mutants, defective in their TGF[Beta] signaling, which can subsequently be functionally complemented to clone the affected genes. We have generated a cell line derived from a hypoxanthine-guanine phosphoribosyl-transferase negative ([HPRT.sup.-]) HT1080 clone that contains the selectable marker Escherichia coli guanine phosphoribosyl-transferase (gpt) linked to a TGF[Beta]-responsive promoter. This cell line proliferates or dies in the appropriate selection medium in response to TGF[Beta]. We have isolated three distinct TGF[Beta]-unresponsive mutants following chemical mutagenesis. Somatic cell hybrids between pairs of individual TGF[Beta]-unresponsive clones reveal that each is in a distinct complementation group. Each mutant clone retains all three TGF[Beta] receptors yet fails to induce a TGF[Beta]-inducible luciferase reporter construct or TGF[Beta]-mediated plasminogen activator inhibitor-1 (PAI-1) expression. Two of the three have an attenuated TGF[Beta]-induced fibronectin response, whereas in the other mutant the fibronectin response is intact. These TGF[Beta]-unresponsive cells should allow selection and identification of signaling molecules through functional complementation.

Transforming growth factor (TGF)-beta produces an increase in the concentration of an intracellular form of apolipoprotein J (apoJ)/clusterin in the nucleus. TGF-beta also causes an rise in the transcription of apoJ gene in lung epithelial cells. ApoJ, an 80 kDa secretory glycoprotein in body fluid is translated from two in-frame ATG sites. The first ATG encodes the secretory form of apoJ and the second ATG encodes a truncated apoJ. The primary sequence of apoJ confirms the presence of the nuclear form.

The adenovirus oncoprotein E1A inactivates cyclin-dependent kinase inhibitor p27(super Kip1) in TGF-beta-treated cells. E1A binds to the kinase inhibitor and abolishes its inhibitory effect, resulting in the restoration of cyclin-cdk2 kinase complex activity. E1A interacts with p27(super Kip1) through sequences located in the C-terminal of p27(Kip1). E1A overcomes the TGF-beta suppression of cell growth by inactivating p27(super Kip 1).

Human brain and human placental cDNA libraries were screened using the yeast two-hybrid method to search for proteins involved in the transmission of signals from activated type I (RI) and type II receptors (RII) of transforming growth factor-beta (TGF-B). The results show that a protein identical to apolipoprotein (apoJ)/clusterin interacts with both RI and RII via its C-terminal 127 amino acid chain. It was also discovered that the 60-kilodalton intracellular form of apoJ is involved in TGF-B receptor processing or TGF-B signaling.