NF-IL6, a member of the basic leucine zipper (bZIP) family transcription factors, is involved in expression of inducible genes involved in immune and inflammatory responses. We observed that coexpression of oncogenic p2l1 stimulated the transactivating activity of NF-IL6 and induced phosphorylation of Thr-235 located just N-terminal NF-IL6 was initially identified as a nuclear factor binding to the interleukin 1 (IL-1) responsive element in the IL-6 gene (1). The cloned NF-IL6 exhibits a homology with CCAAT/ enhancer binding protein (C/EBP), a member of the basic leucine zipper (bZIP) family of transcription factors (2). This protein has recently been reported by other groups under the names AGP/EBP, LAP, IL-6DBP, rNFIL-6, C/EBPP3, and CRP2 (3-8). NF-IL6 activates several acute-phase protein genes through the IL-6 responsive elements, implying that it is a nuclear target for IL-6 signal transduction (5, 9). NF-IL6 has also been shown to be responsible for regulation of the genes encoding albumin, c-fos, and several adipocytespecific proteins. Furthermore, NF-IL6 has been implicated in activation of various genes involved in inflammatory and immune responses, including the IL-8, granulocyte/colonystimulating factor, IL-1, and immunoglobulin genes (10). Thus, NF-IL6 has turned out to be a pleiotropic transactivator involved in signal transduction and cell differentiation.The signal transduction pathway mediated by growth factors and cytokines is initiated by activation of tyrosine kinases. Several cytokines including IL-2, IL-3, IL-4, IL-5, IL-6, and granulocyte-macrophage/colony-stimulating factor activate intracellular tyrosine kinases (11). Recently, the ras-encoded protein has been shown to act downstream of several tyrosine kinases (12)(13)(14). However, signaling events subsequent to ras are still poorly understood except that they involve the activation of several serine/threonine kinases. In the case of the IL-6 signaling process, IL-6-triggered association of IL-6 receptor and gpl3O activates ras in addition to an as yet unidentified tyrosine kinase (14)(15)(16)(17). Recently, gpl3O has been shown to be a common signal transducer for several cytokines, including IL-6, oncostatin M, leukemia inhibitory factor, and ciliary neurotrophic factor, suggesting that NF-IL6 may be the target of a common signal transduction pathway shared by several cytokines (18)(19)(20).As a first step toward understanding the gp130-mediated signaling pathway, we examined the effect of p21ras expression on NF-IL6-mediated transactivation and observed that coexpression of oncogenic p21ras stimulated the transcriptional activity of NF-IL6. Furthermore, we demonstrated that the ras-dependent activation of NF-IL6 was mediated through phosphorylation by mitogen-activated protein (MAP) kinases. §To whom reprint requests should be addressed. MATERIALS AND METHODS 2207The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with...

The complete amino acid sequence of the regulatory subunit of type I cAMP-dependent protein kinase from bovine skeletal muscle is presented. The S-carboxymethylated protein was cleaved with cyanogen bromide to provide a complete set of nonoverlapping fragments. These fragments were overlapped and aligned by using peptides generated by proteolytic cleavage. The protein contains 379 amino acid residues corresponding to a molecular weight of 42 804. As in the type II regulatory subunit of cAMP-dependent protein kinase, a pattern of internal gene duplication is observed, which is consistent with two cAMP-binding domains. The two types of regulatory subunit from type I and type II kinase display similarities in domain substructure and in amino acid sequence, which provide a molecular basis for new insight into their regulatory roles. Detailed analyses of the homology of the regulatory subunits of type I and type II cAMP-dependent protein kinase and of similar relationships to cGMP-dependent protein kinase and Escherichia coli catabolite gene activator protein are presented in accompanying reports from this laboratory [Takio, K., Smith, S. B., Krebs, E. G., Walsh, K., & Titani, K. (1984) Biochemistry (second paper of three in this issue); Takio, K., Wade, R. D., Smith, S. B., Krebs, E. G., Walsh, K. A., & Titani, K. (1984) Biochemistry (third paper of three in this issue)].

The complete amino acid sequence of the light chain of human blood coagulation factor X has been determined by automated Edman degradation of peptides isolated from chemical and enzymatic digests of the carboxymethylated light chain. The protein consists of 139 amino acid residues, which include 11 residues of gamma-carboxyglutamic acid. The first 100 residues of the human factor X light chain exhibit approximately 80% homology when compared to the amino-terminal sequence of bovine factor X light chain. This homology decreases to approximately 50% in the remaining 39 residues of the carboxyl-terminal region of the protein. Proton nuclear magnetic resonance spectroscopy and mass spectrometry analyses of isolated residue 63 identified this residue as L-erythro-beta-hydroxyaspartic acid, a hitherto unrecognized amino acid in proteins. Evidence is also presented for the presence of this residue in the corresponding regions of the light chains of bovine factor X and bovine protein C. The biological function of beta-hydroxyaspartic acid in these proteins is unknown.

The complete amino acid sequence of trypsin from the crayfish Astacus fluviatilis has been determined. The protein was fragmented with cyanogen bromide after S-carboxymethylation of the reduced disulfide bonds and by trypsin after S-carboxymethylation as well as after succinylation of lysine residues and aminoethylation of the reduced disulfide bonds. Peptides were purified by gel filtration and by reversed-phase high-performance liquid chromatography. Stepwise degradation was performed in a spinning cup sequencer. The enzyme contains 237 amino acid residues and has a molecular weight of 25 030. In contrast to bovine trypsin, it contains three rather than six disulfide bonds which are paired in the same fashion as those in trypsin from Streptomyces griseus. The constituents of the active site of bovine trypsin are present in corresponding positions in the crayfish enzyme. Crayfish trypsin shows 43.6% sequence identity with the bovine enzyme as compared to 40.0% identity with the S. griseus enzyme. The present analysis affords the first detailed view into the evolution of trypsins at the invertebrate level.

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