Fully grown mammalian oocytes utilize transcripts synthetized and stored during earlier development. RNA localization followed by a local translation is a mechanism responsible for the regulation of spatial and temporal gene expression. Here we show that the mouse oocyte contains 3 forms of cap-dependent translational repressor expressed on the mRNA level: 4E-BP1, 4E-BP2 and 4E-BP3. However, on...

BACKGROUND Eukaryotic translation initiation factor 4E (eIF4E) plays an important role in plant virus infection as well as the regulation of gene translation. METHODOLOGY/PRINCIPAL FINDINGS Here, we describe the isolation of a cDNA encoding CmeIF(iso)4E (GenBank accession no. JQ904592), an isoform of eIF4E from chrysanthemum, using RACE PCR. We used the CmeIF(iso)4E cDNA for expression profil...

There is mounting evidence that in fat and other insulin-sensitive cells activation of protein synthesis may involve the dissociation of a protein (4E-BP1) from eukaryotic initiation factor (eIF)-4E thus allowing formation of the eIF-4F complex. This study compares the effects of insulin and epidermal growth factor (EGF) on the phosphorylation of 4E-BP1 in fat-cells (followed by gel-shift assay...

Tuxworth, William J., Jr., Hisayasu Wada, Yuji Ishibashi, and Paul J. McDermott. Role of load in regulating eIF-4F complex formation in adult feline cardiocytes. Am. J. Physiol. 277 (Heart Circ. Physiol. 46): H1273–H1282, 1999.— This study examined whether cardiocyte load increases eIF-4F complex formation. To increase load in vitro, adult feline cardiocytes were electrically stimulated to cont...

eIF4E-binding proteins (4E-BPs) are a widespread class of translational regulators that share a canonical (C) eIF4E-binding motif (4E-BM) with eIF4G. Consequently, 4E-BPs compete with eIF4G for binding to the dorsal surface on eIF4E to inhibit translation initiation. Some 4E-BPs contain non-canonical 4E-BMs (NC 4E-BMs), but the contribution of these motifs to the repressive mechanism--and wheth...

BACKGROUND The mammalian target of rapamycin, mTOR, is a serine/threonine kinase that controls cell growth and proliferation via the translation regulators eukaryotic initiation factor 4E (eIF4E) binding protein 1 (4E-BP1) and ribosomal protein S6 kinase 1 (S6K1). We recently identified a TOR signaling (TOS) motif in the N terminus of S6K1 and the C terminus of 4E-BP1 and demonstrated that in S...

PURPOSE Both phosphatidylinositol 3-kinase/AKT and RAS/mitogen-activated protein kinase signal transduction pathways mediate 4E-BP1 phosphorylation, releasing 4E-BP1 from the mRNA cap and permitting translation initiation. Given the prevalence of PTEN and BRAF mutations in melanoma, we first examined translation initiation, as measured by phosphorylated 4E-BP1 (p-4E-BP1), in metastatic melanoma...

This study examined whether cardiocyte load increases eIF-4F complex formation. To increase load in vitro, adult feline cardiocytes were electrically stimulated to contract (1 Hz, 5-ms pulses). eIF-4F complex formation, measured by eIF-4G association with eIF-4E, increased 57 ± 16% after 4 h of contraction compared with controls. eIF-4F complex formation did not increase on electrical stimulati...

BACKGROUND Eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1) is an important factor regulating protein translation. It also impacts proliferation, apoptosis, invasion, and the cell cycle of cancer cells. The aim of this study was to investigate the relationship between 4E-BP1 and human immune status, recognizing immunomodulatory molecules involved in the overexpression of 4...