About: Serine is a(n) research topic. Over the lifetime, 13857 publication(s) have been published within this topic receiving 574113 citation(s). The topic is also known as: L-Ser & (2S)-2-amino-3-hydroxypropanoic acid.
TL;DR: The rapid phosphorylation of BAD following IL-3 connects a proximal survival signal with the BCL-2 family, modulating this checkpoint for apoptosis and enhanced BAD's death-promoting activity.
Abstract: Extracellular survival factors alter a cell's susceptibility to apoptosis, often through posttranslational mechanisms. However, no consistent relationship has been established between such survival signals and the BCL-2 family, where the balance of death agonists versus antagonists determines susceptibility. One distant member, BAD, heterodimerizes with BCL-X L or BCL-2, neutralizing their protective effect and promoting cell death. In the presence of survival factor IL-3, cells phosphorylated BAD on two serine residues embedded in 14-3-3 consensus binding sites. Only the nonphosphorylated BAD heterodimerized with BCL-X L at membrane sites to promote cell death. Phosphorylated BAD was sequestered in the cytosol bound to 14-3-3. Substitution of serine phosphorylation sites further enhanced BAD's death-promoting activity. The rapid phosphorylation of BAD following IL-3 connects a proximal survival signal with the BCL-2 family, modulating this checkpoint for apoptosis.
TL;DR: The rapid degradation of injected alpha- and beta-casein as well as the inverse correlation of PEST regions with intracellular stability indicate that the presence of these regions can result in the rapid intrace cellular degradation of the proteins containing them.
Abstract: The amino acid sequences of ten proteins with intracellular half-lives less than 2 hours contain one or more regions rich in proline (P), glutamic acid (E), serine (S), and threonine (T). These PEST regions are generally, but not always, flanked by clusters containing several positively charged amino acids. Similar inspection of 35 proteins with intracellular half-lives between 20 and 220 hours revealed that only three contain a PEST region. On the basis of this information, it was anticipated that caseins, which contain several PEST sequences, would be rapidly degraded within eukaryotic cells. This expectation was confirmed by red blood cell-mediated microinjection of 125I-labeled caseins into HeLa cells where they exhibited half-lives of less than 2 hours. The rapid degradation of injected alpha- and beta-casein as well as the inverse correlation of PEST regions with intracellular stability indicate that the presence of these regions can result in the rapid intracellular degradation of the proteins containing them.
TL;DR: 'The following abbreviations have been used in the text'; I3-N-uxalyl-L-a,l3diaminu-prupiunic acid; ACPD, Trans-l-aminu-cydupentyl-I,3-dicarbuxylate; AMPA, a aminU-3-hydruxy-5-methyl-isoxazole-4-propionate; AP4, 2-
Abstract: 'The following abbreviations have been used in the text; I3-L-ODAP, I3-N-uxalyl-L-a,l3diaminu-prupiunic acid; ACPD, Trans-l-aminu-cydupentyl-I,3-dicarbuxylate; AMPA, a aminu-3-hydruxy-5-methyl-isoxazole-4-propionate; AP4, 2-amino-4-phosphonobutyrate; AP5, 2-amino-5-phuphonovalerate; ASP, aspartate; CNQX, 6-cyano-7-nitro-quinoxaline-2,3-dione; CPP, 3-(2-earboxypiperazin-4-yl)prupyl-l -phosphate; cyelo-Leu, eydo-Ieucine; DAA, D-a amino-adipate; DGG, y-D-glutamylglycine; DNQX, 6,7-dinitro-quinoxaline-2,3dione; EAA, excitatory amino acids; GABA, gamma-aminu-butyric acid; GDEE, glutamate diethyl ester; GLU, glutamate; GL Y, glycine; HA-966, 3-amino-l-hydroxypyrrolidone-2; lBO, ibotenate; IP, inositol phosphate; KA, kainate; KYN, kynurenate; MK-801, dibenzoeyclohepteneimine; NMDA, N-methyl-D-aspartate; PCP, phencyclidine; QA, quisqualate; SER, serine; SOP, serine O-phosphate; TCP, 1-[1-(2-thienyl)-eyclohexyIJpiperidine
TL;DR: The data suggest that in vivo CAP1–4 are the APO‐1 apoptosis‐transducing molecules.
Abstract: APO-1 (Fas/CD95), a member of the tumor necrosis factor receptor superfamily, induces apoptosis upon receptor oligomerization. In a search to identify intracellular signaling molecules coupling to oligomerized APO-1, several cytotoxicity-dependent APO-1-associated proteins (CAP) were immunoprecipitated from the apoptosis-sensitive human leukemic T cell line HUT78 and the lymphoblastoid B cell line SKW6.4. CAP1-3 (27-29 kDa) and CAP4 (55 kDa), instantly detectable after the crosslinking of APO-1, were associated only with aggregated (the signaling form of APO-1) and not with monomeric APO-1. CAP1 and CAP2 were identified as serine phosphorylated MORT1/FADD. The association of CAP1-4 with APO-1 was not observed with C-terminally truncated non-signaling APO-1. In addition, CAP1 and CAP2 did not associate with an APO-1 cytoplasmic tail carrying the lprcg amino acid replacement. Moreover, no APO-1-CAP association was found in the APO-1+, anti-APO-1-resistant pre-B cell line Boe. Our data suggest that in vivo CAP1-4 are the APO-1 apoptosis-transducing molecules.
Abstract: Protein kinases are coded by more than 2,000 genes and thus constitute the largest single enzyme family in the human genome. Most cellular processes are in fact regulated by the reversible phosphorylation of proteins on serine, threonine, and tyrosine residues. At least 30% of all proteins are thought to contain covalently bound phosphate. Despite the importance and widespread occurrence of this modification, identification of sites of protein phosphorylation is still a challenge, even when performed on highly purified protein. Reported here is methodology that should make it possible to characterize most, if not all, phosphoproteins from a whole-cell lysate in a single experiment. Proteins are digested with trypsin and the resulting peptides are then converted to methyl esters, enriched for phosphopeptides by immobilized metal-affinity chromatography (IMAC), and analyzed by nanoflow HPLC/electrospray ionization mass spectrometry. More than 1,000 phosphopeptides were detected when the methodology was applied to the analysis of a whole-cell lysate from Saccharomyces cerevisiae. A total of 216 peptide sequences defining 383 sites of phosphorylation were determined. Of these, 60 were singly phosphorylated, 145 doubly phosphorylated, and 11 triply phosphorylated. Comparison with the literature revealed that 18 of these sites were previously identified, including the doubly phosphorylated motif pTXpY derived from the activation loop of two mitogen-activated protein (MAP) kinases. We note that the methodology can easily be extended to display and quantify differential expression of phosphoproteins in two different cell systems, and therefore demonstrates an approach for "phosphoprofiling" as a measure of cellular states.