scholarly journals Dual Cyclin-Binding Domains Are Required for p107 To Function as a Kinase Inhibitor

1998 ◽  
Vol 18 (9) ◽  
pp. 5380-5391 ◽  
Author(s):  
Enrique Castaño ◽  
Yelena Kleyner ◽  
Brian David Dynlacht
Keyword(s):  
Mammalian Cells ◽  
Kinase Inhibitor ◽  
Point Mutations ◽  
Growth Suppression ◽  
Kinase Substrate ◽  
Amino Terminal ◽  
Terminal Domain ◽  
Amino Terminal Domain

ABSTRACT The retinoblastoma (pRB) family of proteins includes three proteins known to suppress growth of mammalian cells. Previously we had found that growth suppression by two of these proteins, p107 and p130, could result from the inhibition of associated cyclin-dependent kinases (cdks). One important unresolved issue, however, is the mechanism through which inhibition occurs. Here we present in vivo and in vitro evidence to suggest that p107 is a bona fide inhibitor of both cyclin A-cdk2 and cyclin E-cdk2 that exhibits an inhibitory constant (Ki ) comparable to that of the cdk inhibitor p21/WAF1. In contrast, pRB is unable to inhibit cdks. Further reminiscent of p21, a second cyclin-binding site was mapped to the amino-terminal portions of p107 and p130. This amino-terminal domain is capable of inhibiting cyclin-cdk2 complexes, although it is not a potent substrate for these kinases. In contrast, a carboxy-terminal fragment of p107 that contains the previously identified cyclin-binding domain serves as an excellent kinase substrate although it is unable to inhibit either kinase. Clustered point mutations suggest that the amino-terminal domain is functionally important for cyclin binding and growth suppression. Moreover, peptides spanning the cyclin-binding region are capable of interfering with p107 binding to cyclin-cdk2 complexes and kinase inhibition. Our ability to distinguish between p107 and p130 as inhibitors rather than simple substrates suggests that these proteins may represent true inhibitors of cdks.

scholarly journals The amino-terminal domain of pyrrolysyl-tRNA synthetase is dispensable in vitro but required for in vivo activity

FEBS Letters ◽  
2007 ◽  
Vol 581 (17) ◽  
pp. 3197-3203 ◽  
Author(s):  
Stephanie Herring ◽  
Alexandre Ambrogelly ◽  
Sarath Gundllapalli ◽  
Patrick O'Donoghue ◽  
Carla R. Polycarpo ◽  
...  
Keyword(s):  
Trna Synthetase ◽  
Amino Terminal ◽  
Terminal Domain ◽  
Amino Terminal Domain

scholarly journals Residues near the Amino Terminus of Rns Are Essential for Positive Autoregulation and DNA Binding

2008 ◽  
Vol 190 (7) ◽  
pp. 2279-2285 ◽  
Author(s):  
Georgeta N. Basturea ◽  
Maria D. Bodero ◽  
Mario E. Moreno ◽  
George P. Munson
Keyword(s):  
Dna Binding ◽  
Amino Terminus ◽  
Amino Terminal ◽  
Terminal Domain ◽  
Carboxy Terminal Domain ◽  
Carboxy Terminal ◽  
Amino Terminal Domain ◽  
Regulated Promoters

ABSTRACT Most members of the AraC/XylS family contain a conserved carboxy-terminal DNA binding domain and a less conserved amino-terminal domain involved in binding small-molecule effectors and dimerization. However, there is no evidence that Rns, a regulator of enterotoxigenic Escherichia coli virulence genes, responds to an effector ligand, and in this study we found that the amino-terminal domain of Rns does not form homodimers in vivo. Exposure of Rns to the chemical cross-linker glutaraldehyde revealed that the full-length protein is also a monomer in vitro. Nevertheless, deletion analysis of Rns demonstrated that the first 60 amino acids of the protein are essential for the activation and repression of Rns-regulated promoters in vivo. Amino-terminal truncation of Rns abolished DNA binding in vitro, and two randomly generated mutations, I14T and N16D, that independently abolished Rns autoregulation were isolated. Further analysis of these mutations revealed that they have disparate effects at other Rns-regulated promoters and suggest that they may be involved in an interaction with the carboxy-terminal domain of Rns. Thus, evolution may have preserved the amino terminus of Rns because it is essential for the regulator's activity even though it apparently lacks the two functions, dimerization and ligand binding, usually associated with the amino-terminal domains of AraC/XylS family members.

scholarly journals BBK07, a Dominant In Vivo Antigen of Borrelia burgdorferi, Is a Potential Marker for Serodiagnosis of Lyme Disease

2009 ◽  
Vol 16 (11) ◽  
pp. 1569-1575 ◽  
Author(s):  
Adam S. Coleman ◽  
Utpal Pal
Keyword(s):  
Lyme Disease ◽  
Borrelia Burgdorferi ◽  
Amino Acid Identity ◽  
Amino Terminal ◽  
Terminal Domain ◽  
Potential Marker ◽  
Mammalian Infection ◽  
Amino Terminal Domain

ABSTRACT One of the recently identified Borrelia burgdorferi immunogens, BBK07, is characterized for its expression in the spirochete infection cycle and evaluated for its potential use as a serodiagnostic marker for Lyme disease. We show that the BBK07 gene is expressed at extremely low levels in vitro and in ticks but is dramatically induced by spirochetes once introduced into the host and is highly expressed throughout mammalian infection. In contrast, the expression of BBK12, a paralog of BBK07 with 87% amino acid identity, although expressed in vitro, remained undetectable in vivo throughout murine infection and in ticks. BBK07 is localized in the outer membrane, and the amino-terminal domain of the antigen is exposed on the microbial surface. A truncated BBK07 protein representing the amino-terminal domain is able to effectively detect antibodies to B. burgdorferi, both in experimentally infected mice and in humans. Further characterization of the immunodominant antigens of B. burgdorferi, such as BBK07, could contribute to the development of novel serodiagnostic markers for detection of Lyme disease.

scholarly journals ADA3, a putative transcriptional adaptor, consists of two separable domains and interacts with ADA2 and GCN5 in a trimeric complex.

1995 ◽  
Vol 15 (3) ◽  
pp. 1203-1209 ◽  
Author(s):  
J Horiuchi ◽  
N Silverman ◽  
G A Marcus ◽  
L Guarente
Keyword(s):  
Activation Domains ◽  
Amino Terminal ◽  
Terminal Domain ◽  
Trimeric Complex ◽  
Nonoverlapping Domains ◽  
Carboxyl Terminal Domain ◽  
Carboxyl Terminal ◽  
Amino Terminal Domain

Mutations in yeast ADA2, ADA3, and GCN5 weaken the activation potential of a subset of acidic activation domains. In this report, we show that their gene products form a heterotrimeric complex in vitro, with ADA2 as the linchpin holding ADA3 and GCN5 together. Further, activation by LexA-ADA3 fusions in vivo are regulated by the levels of ADA2. Combined with a prior observation that LexA-ADA2 fusions are regulated by the levels of ADA3 (N. Silverman, J. Agapite, and L. Guarente, Proc. Natl. Acad. Sci. USA 91:11665-11668, 1994), this finding suggests that these proteins also form a complex in cells. ADA3 can be separated into two nonoverlapping domains, an amino-terminal domain and a carboxyl-terminal domain, which do not separately complement the slow-growth phenotype or transcriptional defect of a delta ada3 strain but together supply full complementation. The carboxyl-terminal domain of ADA3 alone suffices for heterotrimeric complex formation in vitro and activation of LexA-ADA2 in vivo. We present a model depicting the ADA complex as a coactivator in which the ADA3 amino-terminal domain mediates an interaction between activation domains and the ADA complex.

scholarly journals Characterization of LDD-2633 as a Novel RET Kinase Inhibitor with Anti-Tumor Effects in Thyroid Cancer

2021 ◽  
Vol 14 (1) ◽  
pp. 38
Author(s):  
Hyo Jeong Lee ◽  
Pyeonghwa Jeong ◽  
Yeongyu Moon ◽  
Jungil Choi ◽  
Jeong Doo Heo ◽  
...  
Keyword(s):  
Thyroid Cancer ◽  
Thyroid Carcinoma ◽  
Kinase Inhibitor ◽  
Point Mutations ◽  
Carcinoma Cells ◽  
Medullary Thyroid ◽  
Potent Inhibition ◽  
Kinase Inhibitory Activity

Rearranged during transfection (RET), a receptor tyrosine kinase, is activated by glial cell line-derived neurotrophic factor family ligands. Chromosomal rearrangement or point mutations in RET are observed in patients with papillary thyroid and medullary thyroid carcinomas. Oncogenic alteration of RET results in constitutive activation of RET activity. Therefore, inhibiting RET activity has become a target in thyroid cancer therapy. Here, the anti-tumor activity of a novel RET inhibitor was characterized in medullary thyroid carcinoma cells. The indirubin derivative LDD-2633 was tested for RET kinase inhibitory activity. In vitro, LDD-2633 showed potent inhibition of RET kinase activity, with an IC50 of 4.42 nM. The growth of TT thyroid carcinoma cells harboring an RET mutation was suppressed by LDD-2633 treatment via the proliferation suppression and the induction of apoptosis. The effects of LDD-2633 on the RET signaling pathway were examined; LDD-2633 inhibited the phosphorylation of the RET protein and the downstream molecules Shc and ERK1/2. Oral administration of 20 or 40 mg/kg of LDD-2633 induced dose-dependent suppression of TT cell xenograft tumor growth. The in vivo and in vitro experimental results supported the potential use of LDD-2633 as an anticancer drug for thyroid cancers.

Functional interaction between p21rap1A and components of the budding pathway in Saccharomyces cerevisiae

1992 ◽  
Vol 12 (9) ◽  
pp. 4084-4092
Author(s):  
P C McCabe ◽  
H Haubruck ◽  
P Polakis ◽  
F McCormick ◽  
M A Innis
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mammalian Cells ◽  
Bound States ◽  
Yeast Cells ◽  
Temperature Sensitive ◽  
Wild Type ◽  
Amino Terminal ◽  
Loop Region

The rap1A gene encodes a 21-kDa, ras-related GTP-binding protein (p21rap1A) of unknown function. A close structural homolog of p21rap1A (65% identity in the amino-terminal two-thirds) is the RSR1 gene product (Rsr1p) of Saccharomyces cerevisiae. Although Rsr1p is not essential for growth, its presence is required for nonrandom selection of bud sites. To assess the similarity of these proteins at the functional level, wild-type and mutant forms of p21rap1A were tested for complementation of activities known to be fulfilled by Rsr1p. Expression of p21rap1A, like multicopy expression of RSR1, suppressed the conditional lethality of a temperature-sensitive cdc24 mutation. Point mutations predicted to affect the localization of p21rap1A or its ability to cycle between GDP and GTP-bound states disrupted suppression of cdc24ts, while other mutations in the 61-65 loop region improved suppression. Expression of p21rap1A could not, however, suppress the random budding phenotype of rsr1 cells. p21rap1A also apparently interfered with the normal activity of Rsrlp, causing random budding in diploid wild-type cells, suggesting an inability of p21rap1A to interact appropriately with Rsr1p regulatory proteins. Consistent with this hypothesis, we found an Rsr1p-specific GTPase-activating protein (GAP) activity in yeast membranes which was not active toward p21rap1A, indicating that p21rap1A may be predominantly GTP bound in yeast cells. Coexpression of human Rap1-specific GAP suppressed the random budding due to expression of p21rap1A or its derivatives, including Rap1AVal-12. Although Rap1-specific GAP stimulated the GTPase of Rsr1p in vitro, it did not dominantly interfere with Rsr1p function in vivo. A chimera consisting of Rap1A1-165::Rsr1p166-272 did not exhibit normal Rsr1p function in the budding pathway. These results indicated that p21rap1A and Rsr1p share at least partial functional homology, which may have implications for p21rap1A function in mammalian cells.

scholarly journals Functions of the C-Terminal Domain of Varicella-Zoster Virus Glycoprotein E in Viral Replication In Vitro and Skin and T-Cell Tropism In Vivo

2004 ◽  
Vol 78 (22) ◽  
pp. 12406-12415 ◽  
Author(s):  
Jennifer Moffat ◽  
Chengjun Mo ◽  
Jason J. Cheng ◽  
Marvin Sommer ◽  
Leigh Zerboni ◽  
...  
Keyword(s):  
T Cell ◽  
Viral Replication ◽  
Varicella Zoster Virus ◽  
Point Mutations ◽  
Glycoprotein E ◽  
Varicella Zoster ◽  
Terminal Domain ◽  
C Terminus

ABSTRACT Varicella-zoster virus (VZV) glycoprotein E (gE) is essential for VZV replication. To further analyze the functions of gE in VZV replication, a full deletion and point mutations were made in the 62-amino-acid (aa) C-terminal domain. Targeted mutations were introduced in YAGL (aa 582 to 585), which mediates gE endocytosis, AYRV (aa 568 to 571), which targets gE to the trans-Golgi network (TGN), and SSTT, an “acid cluster” comprising a phosphorylation motif (aa 588 to 601). Substitutions Y582G in YAGL, Y569A in AYRV, and S593A, S595A, T596A, and T598A in SSTT were introduced into the viral genome by using VZV cosmids. These experiments demonstrated a hierarchy in the contributions of these C-terminal motifs to VZV replication and virulence. Deletion of the gE C terminus and mutation of YAGL were lethal for VZV replication in vitro. Mutations of AYRV and SSTT were compatible with recovery of VZV, but the AYRV mutation resulted in rapid virus spread in vitro and the SSTT mutation resulted in higher virus titers than were observed for the parental rOka strain. When the rOka-gE-AYRV and rOka-gE-SSTT mutants were evaluated in skin and T-cell xenografts in SCIDhu mice, interference with TGN targeting was associated with substantial attenuation, especially in skin, whereas the SSTT mutation did not alter VZV infectivity in vivo. These results provide the first information about how targeted mutations of this essential VZV glycoprotein affect viral replication in vitro and VZV virulence in dermal and epidermal cells and T cells within intact tissue microenvironments in vivo.

scholarly journals Mutant alcohol dehydrogenase (ADH III) presequences that affect both in vitro mitochondrial import and in vitro processing by the matrix protease.

1990 ◽  
Vol 10 (6) ◽  
pp. 2801-2808 ◽  
Author(s):  
D T Mooney ◽  
D B Pilgrim ◽  
E T Young
Keyword(s):  
Point Mutations ◽  
Wild Type ◽  
Urea Treatment ◽  
Amino Terminal ◽  
In Vitro Processing ◽  
The Matrix ◽  
Terminal Amino ◽  
Processing Protease

Point mutations in the presequence of the mitochondrial alcohol dehydrogerase isoenzyme (ADH III) have been shown to affect either the import of the precursor protein into yeast mitochondria in vivo or its processing within the organelle. In the present work, the behavior of these mutants during in vitro import into isolated mitochondria was investigated. All point mutants tested were imported with a slower initial rate than that of the wild-type precursor. This defect was corrected when the precursors were treated with urea prior to import. Once imported, the extent of processing to the mature form of mutant precursors varied greatly and correlated well with the defects observed in vivo. This result was not affected by prior urea treatment. When matrix extracts enriched for the processing protease were used, this defect was shown to be due to failure of the protease to efficiently recognize or cleave the presequence, rather than to a lack of access to the precursor. The rate of import of two ADH III precursors bearing internal deletions in the leader sequence was similar to those of the point mutants, whereas a deletion leading to the removal of the 15 amino-terminal amino acids was poorly imported. The mature amino terminus of wild-type ADH III was determined to be Gln-25. Mutant m01 (Ser-26 to Phe), which reduced the efficiency of cleavage in vitro by 80%, was cleaved at the correct site.

scholarly journals Amino-Terminal Domain Exchange Redirects Origin-Specific Interactions of Adeno-Associated Virus Rep78 In Vitro

2001 ◽  
Vol 75 (7) ◽  
pp. 3230-3239 ◽  
Author(s):  
Miran Yoon ◽  
Deborah H. Smith ◽  
Peter Ward ◽  
Francisco J. Medrano ◽  
Aneel K. Aggarwal ◽  
...  
Keyword(s):  
Dna Replication ◽  
Catalytic Domain ◽  
Adeno Associated Virus ◽  
Free System ◽  
Site Specific ◽  
Amino Terminal ◽  
Terminal Domain ◽  
Site Specific Integration ◽  
Amino Terminal Domain

ABSTRACT The unique ability of adeno-associated virus type 2 (AAV) to site-specifically integrate its genome into a defined sequence on human chromosome 19 (AAVS1) makes it of particular interest for use in targeted gene delivery. The objective underlying this study is to provide evidence for the feasibility of retargeting site-specific integration into selected loci within the human genome. Current models postulate that AAV DNA integration is initiated through the interactions of the products of a single viral open reading frame,REP, with sequences present in AAVS1 that resemble the minimal origin for AAV DNA replication. Here, we present a cell-free system designed to dissect the Rep functions required to target site-specific integration using functional chimeric Rep proteins derived from AAV Rep78 and Rep1 of the closely related goose parvovirus. We show that amino-terminal domain exchange efficiently redirects the specificity of Rep to the minimal origin of DNA replication. Furthermore, we establish that the amino-terminal 208 amino acids of Rep78/68 constitute a catalytic domain of Rep sufficient to mediate site-specific endonuclease activity.

scholarly journals The Novel Adaptor Protein Tks4 (SH3PXD2B) Is Required for Functional Podosome Formation

2009 ◽  
Vol 20 (5) ◽  
pp. 1302-1311 ◽  
Author(s):  
Matthew D. Buschman ◽  
Paul A. Bromann ◽  
Pilar Cejudo-Martin ◽  
Fang Wen ◽  
Ian Pass ◽  
...  
Keyword(s):  
Protein Tyrosine Kinase ◽  
Metastatic Cancer ◽  
Adaptor Protein ◽  
Membrane Structures ◽  
Kinase Substrate ◽  
Amino Terminal ◽  
Ecm Degradation ◽  
Membrane Type

Metastatic cancer cells have the ability to both degrade and migrate through the extracellular matrix (ECM). Invasiveness can be correlated with the presence of dynamic actin-rich membrane structures called podosomes or invadopodia. We showed previously that the adaptor protein tyrosine kinase substrate with five Src homology 3 domains (Tks5)/Fish is required for podosome/invadopodia formation, degradation of ECM, and cancer cell invasion in vivo and in vitro. Here, we describe Tks4, a novel protein that is closely related to Tks5. This protein contains an amino-terminal Phox homology domain, four SH3 domains, and several proline-rich motifs. In Src-transformed fibroblasts, Tks4 is tyrosine phosphorylated and predominantly localized to rosettes of podosomes. We used both short hairpin RNA knockdown and mouse embryo fibroblasts lacking Tks4 to investigate its role in podosome formation. We found that lack of Tks4 resulted in incomplete podosome formation and inhibited ECM degradation. Both phenotypes were rescued by reintroduction of Tks4, whereas only podosome formation, but not ECM degradation, was rescued by overexpression of Tks5. The tyrosine phosphorylation sites of Tks4 were required for efficient rescue. Furthermore, in the absence of Tks4, membrane type-1 matrix metalloproteinase (MT1-MMP) was not recruited to the incomplete podosomes. These findings suggest that Tks4 and Tks5 have overlapping, but not identical, functions, and implicate Tks4 in MT1-MMP recruitment and ECM degradation.

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