scholarly journals Leucine zipper motif in porcine renin-binding protein (RnBP) and its relationship to the formation of an RnBP-renin heterodimer and an RnBP homodimer

1991 ◽  
Vol 266 (18) ◽  
pp. 11896-11900
Author(s):  
H. Inoue ◽  
S. Takahashi ◽  
K. Fukui ◽  
Y. Miyake
Keyword(s):  
Leucine Zipper ◽  
Binding Protein ◽  
Leucine Zipper Motif

scholarly journals Molecular cloning of a novel actin-binding protein, p57, with a WD repeat and a leucine zipper motif

FEBS Letters ◽  
1995 ◽  
Vol 364 (3) ◽  
pp. 283-288 ◽  
Author(s):  
Kensuke Suzuki ◽  
Jun Nishihata ◽  
Yuko Arai ◽  
Nakayuki Honma ◽  
Kazuo Yamamoto ◽  
...  
Keyword(s):  
Molecular Cloning ◽  
Leucine Zipper ◽  
Binding Protein ◽  
Actin Binding ◽  
Leucine Zipper Motif ◽  
Actin Binding Protein ◽  
Wd Repeat

scholarly journals Homotypic dimerization of the actin-binding protein p57/coronin-1 mediated by a leucine zipper motif in the C-terminal region

2005 ◽  
Vol 387 (2) ◽  
pp. 325-331 ◽  
Author(s):  
Teruaki OKU ◽  
Saotomo ITOH ◽  
Rie ISHII ◽  
Kensuke SUZUKI ◽  
William M. NAUSEEF ◽  
...  
Keyword(s):  
Leucine Zipper ◽  
Fluorescent Protein ◽  
Binding Protein ◽  
Coiled Coil ◽  
Terminal Region ◽  
Full Length ◽  
Actin Binding ◽  
Leucine Zipper Motif ◽  
Actin Binding Protein ◽  
Coiled Coil Domain

The actin-binding protein p57/coronin-1, a member of the coronin protein family, is selectively expressed in immune cells, and has been implicated in leucocyte migration and phagocytosis by virtue of its interaction with F-actin (filamentous actin). We previously identified two sites in the N-terminal region of p57/coronin-1 by which it binds actin, and in the present study we examine the role of the leucine zipper motif located in the C-terminal coiled-coil domain in mediating the homotypic association of p57/coronin-1. Recombinant p57/coronin-1 protein in solution formed a homodimer, as analysed by Superose 12 column chromatography and by sucrose density gradient centrifugation. In vivo, a truncated form consisting of the C-terminal coiled-coil domain co-precipitated with full-length p57/coronin-1 when both were co-expressed in COS-1 cells. A chimaeric construct composed of the C-terminal domain of p57/coronin-1 (which lacks the actin-binding sites) fused with green fluorescent protein co-localized with cortical F-actin-rich regions in COS-1 cells only when full-length p57/coronin-1 was expressed simultaneously in the cells, suggesting that the C-terminal region is required for the homotypic association of p57/coronin-1. Furthermore, p57LZ, a polypeptide consisting of the C-terminal 90 amino acid residues of p57/coronin-1, was sufficient for dimerization. When two leucine residues out of the four that constitute the leucine zipper structure in p57LZ or full-length p57 were replaced with alanine residues, the mutants failed to form homodimers. Taken together, these results demonstrate that p57/coronin-1 forms homodimers, that the association is mediated by the leucine zipper structure in the C-terminal region, and that it plays a role in the cross-linking of F-actin in the cell.

scholarly journals Mating Type in Chlamydomonas Is Specified by mid, the Minus-Dominance Gene

Genetics ◽  
1997 ◽  
Vol 146 (3) ◽  
pp. 859-869 ◽  
Author(s):  
Patrick J Ferris ◽  
Ursula W Goodenough
Keyword(s):  
Transcription Factor ◽  
Mating Type ◽  
Codon Bias ◽  
Leucine Zipper ◽  
Laboratory Strain ◽  
Leucine Zipper Motif ◽  
Type Locus ◽  
Diploid Cells ◽  
Necessary And Sufficient

Diploid cells of Chlamydomonas reinhardtii that are heterozygous at the mating-type locus (mt  +/mt  –) differentiate as minus gametes, a phenomenon known as minus dominance. We report the cloning and characterization of a gene that is necessary and sufficient to exert this minus dominance over the plus differentiation program. The gene, called mid, is located in the rearranged (R) domain of the mt  – locus, and has duplicated and transposed to an autosome in a laboratory strain. The imp11 mt  – mutant, which differentiates as a fusion-incompetent plus gamete, carries a point mutation in mid. Like the fus1 gene in the mt  + locus, mid displays low codon bias compared with other nuclear genes. The mid sequence carries a putative leucine zipper motif, suggesting that it functions as a transcription factor to switch on the minus program and switch off the plus program of gametic differentiation. This is the first sex-determination gene to be characterized in a green organism.

scholarly journals cDNA cloning and expression of oxysterol-binding protein, an oligomer with a potential leucine zipper

1989 ◽  
Vol 264 (28) ◽  
pp. 16798-16803
Author(s):  
P A Dawson ◽  
N D Ridgway ◽  
C A Slaughter ◽  
M S Brown ◽  
J L Goldstein
Keyword(s):  
Cdna Cloning ◽  
Leucine Zipper ◽  
Binding Protein ◽  
Cloning And Expression ◽  
Oxysterol Binding Protein

scholarly journals SARP, a new alternatively spliced protein phosphatase 1 and DNA interacting protein

2007 ◽  
Vol 402 (1) ◽  
pp. 187-196 ◽  
Author(s):  
Gareth J. Browne ◽  
Margarida Fardilha ◽  
Senga K. Oxenham ◽  
Wenjuan Wu ◽  
Nicholas R. Helps ◽  
...  
Keyword(s):  
Protein Phosphatase ◽  
Mammalian Cells ◽  
Leucine Zipper ◽  
Transforming Growth Factor ◽  
Binding Protein ◽  
Transforming Growth Factor Β ◽  
Ankyrin Repeat ◽  
Protein Phosphatase 1 ◽  
Binding Motif ◽  
Alternative Mrna Splicing

PP1 (protein phosphatase 1) is a ubiquitously expressed serine/threonine-specific protein phosphatase whose activity towards different substrates appears to be mediated via binding to specific proteins that play critical regulatory and targeting roles. In the present paper we report the cloning and characterization of a new protein, termed SARP (several ankyrin repeat protein), which is shown to interact with all isoforms of PP1 by a variety of techniques. A region encompassing a consensus PP1-binding motif in SARP (K354VHF357) modulates endogenous SARP–PP1 activity in mammalian cells. This SARP–PP1 interaction motif lies partially within the first ankyrin repeat in contrast with other proteins [53BP2 (p53 binding protein 2), MYPT1/M110/MBS (myosin binding protein of PP1) and TIMAP (transforming growth factor β inhibited, membrane-associated protein)], where a PP1-binding motif precedes the ankyrin repeats. Alternative mRNA splicing produces several isoforms of SARP from a single human gene at locus 11q14. SARP1 and/or SARP2 (92–95 kDa) are ubiquitously expressed in all tissues with high levels in testis and sperm, where they are shown to interact with both PP1γ1 and PP1γ2. SARP3 (65 kDa) is most abundant in brain where SARP isoforms interact with both PP1α and PP1γ1. SARP is highly abundant in the nucleus of mammalian cells, consistent with the putative nuclear localization signal at the N-terminus. The presence of a leucine zipper near the C-terminus of SARP1 and SARP2, and the binding of mammalian DNA to SARP2, suggests that SARP1 and SARP2 may be transcription factors or DNA-associated proteins that modulate gene expression.

A cDNA for a human cyclic AMP response element-binding protein which is distinct from CREB and expressed preferentially in brain

1990 ◽  
Vol 10 (4) ◽  
pp. 1347-1357
Author(s):  
C J Kara ◽  
H C Liou ◽  
L B Ivashkiv ◽  
L H Glimcher
Keyword(s):  
Dna Binding ◽  
Cyclic Amp ◽  
Leucine Zipper ◽  
Binding Protein ◽  
Structural Similarity ◽  
Response Element ◽  
Cellular Genes ◽  
Viral Promoters ◽  
Element Binding Protein ◽  
Cyclic Amp Response Element

The cyclic AMP response element (CRE) is found in many cellular genes regulated by cyclic AMP, and similar elements are present in the early genes of adenovirus that are activated by E1A. The transcription factor CREB has previously been shown to bind this site, and cDNAs for CREB have recently been characterized. We report here the isolation of a cDNA encoding a human DNA-binding protein that also recognizes this motif in cellular and viral promoters. This protein, HB16, displays structural similarity to CREB and to c-Jun and c-Fos, which bind the related 12-O-tetradecanoylphorbol-13-acetate response element (TRE). HB16 contains a highly basic, putative DNA-binding domain and a leucine zipper structure thought to be involved in dimerization. Deletional analysis of HB16 demonstrated that the leucine zipper is required for its interaction with DNA. In addition, HB16 could form a complex with c-Jun but not with c-Fos. Despite its structural similarity to c-Jun and c-Fos and its interaction with c-Jun, HB16 had approximately a 10-fold-lower affinity for the TRE sequence than for the CRE sequence. Although HB16 and CREB both recognized the CRE motif, an extensive binding analysis of HB16 revealed differences in the fine specificity of binding of the two proteins. HB16 mRNA was found at various levels in many human tissues but was most abundant in brain, where its expression was widespread. The existence of more than one CRE-binding protein suggests that the CRE motif could serve multiple regulatory functions.

DDRE-30. CELL-PENETRATING PEPTIDE ANTAGONIST OF CCAAT/ENHANCER BINDING PROTEIN ß DISPLAYS POTENT ANTI-GLIOBLASTOMA ACTIVITY

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi80-vi81
Author(s):  
Jim Rotolo ◽  
Lila Ghamsari ◽  
Ricardo Ramierez ◽  
Mark Koester ◽  
Siok Leong ◽  
...  
Keyword(s):  
Gene Expression ◽  
Leucine Zipper ◽  
Binding Protein ◽  
Xenograft Model ◽  
Mesenchymal Transition ◽  
Enhancer Binding Protein ◽  
Ccaat Enhancer Binding Protein ◽  
Subcutaneous Xenograft ◽  
Peptide Antagonist ◽  
Anti Tumor Activity

Abstract CCAAT/Enhancer Binding Protein Beta (C/EBPß) is a transcription factor overexpressed in glioblastoma (GBM). Mechanistically, C/EBPß is a master regulator of mesenchymal transition in GBM, and its increased expression correlates with mesenchymal differentiation and predicts poor clinical outcome. C/EBPß activity requires dimerization with co-factors such as CREB/ATF family members via leucine zipper interactions. ST101 is a novel peptide antagonist of C/EBPß currently being evaluated in a Phase 1/2 clinical study in patients with advanced unresectable and metastatic solid tumors. ST101 binds to the C/EBPß leucine zipper, thereby preventing dimer formation and inhibiting its transcriptional activity, resulting in selective tumor cell cytotoxicity. Here, we describe ST101 non-clinical anti-tumor activity against GBM. In vitro studies in T98G and U251 cells demonstrate ST101 dose-dependent impact of cell viability (EC50 of 2.2 and 1.2 μM, respectively), accompanied by significant impact on C/EBPß-mediated gene expression as determined by qPCR analysis. In contrast, normal human mononuclear and epithelial cells were not sensitive to ST101 (EC50 > 80 μM). In vivo, ST101 displayed significant anti-tumor activity in a U251 GBM subcutaneous xenograft model, resulting in 81.4% tumor growth inhibition (TGI) vs. control and undetectable tumors in 50% of animals. Following ST101 exposure tumors displayed reduced BIRC3 and ID2 gene expression, and significantly increased cleaved caspase 3 immunostaining indicative of cell death induction. In U251 tumors, subtherapeutic ST101 (< 5% TGI) in combination with temozolomide (< 5% TGI) resulted in 52.8% TGI, significantly greater than either single-agent alone. Similarly, in a temozolomide-refractory T98G GBM subcutaneous xenograft model, ST101 (41.6% TGI) in combination with TMZ (< 5% TGI) resulted in significant anti-GBM response (72.4% TGI). These data emphasize the potential of ST101 as a potent peptide therapeutic for GBM.

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