PubMed Health⌕ Search

Biomedical subjects

Drew M Lowery

Publications and source records attributed to Drew M Lowery.

7 recordsLinked to original sources
PubMed2006

Polo-like kinase Cdc5 controls the local activation of Rho1 to promote cytokinesis.

The links between the cell cycle machinery and the cytoskeletal proteins controlling cytokinesis are poorly understood. The small guanine nucleotide triphosphate (GTP)-binding protein RhoA stimulates type II myosin contractility and formin-dependent assembly of the cytokinetic actin contractile ring. We found that budding yeast Polo-like kinase Cdc5 controls the targeting and activation of Rho1 (RhoA) at the division site via Rho1 guanine nucleotide exchange factors. This role of Cdc5 (Polo-like kinase) in regulating Rho1 is likely to be relevant to cytokinesis and asymmetric cell division in other organisms.

Actins↗
PubMed2005

Natural-like function in artificial WW domains.

Protein sequences evolve through random mutagenesis with selection for optimal fitness. Cooperative folding into a stable tertiary structure is one aspect of fitness, but evolutionary selection ultimately operates on function, not on structure. In the accompanying paper, we proposed a model for the evolutionary constraint on a small protein interaction module (the WW domain) through application of the SCA, a statistical analysis of multiple sequence alignments. Construction of artificial protein sequences directed only by the SCA showed that the information extracted by this analysis is sufficient to engineer the WW fold at atomic resolution. Here, we demonstrate that these artificial WW sequences function like their natural counterparts, showing class-specific recognition of proline-containing target peptides. Consistent with SCA predictions, a distributed network of residues mediates functional specificity in WW domains. The ability to recapitulate natural-like function in designed sequences shows that a relatively small quantity of sequence information is sufficient to specify the global energetics of amino acid interactions.

Amino Acid Sequence↗
PubMed2005

Structure and function of Polo-like kinases.

Polo-like kinases play critical roles during multiple stages of cell cycle progression. All Polo-like kinases contain an N-terminal Ser/Thr kinase catalytic domain and a C-terminal region that contains one or two Polo-boxes. For Polo-like kinase 1, 2, and 3, and their homologs, the entire C-terminal region, including both Polo-boxes, functions as a single modular phosphoserine/threonine-binding domain known as the Polo-box domain (PBD). In the absence of a bound substrate, the PBD inhibits the basal activity of the kinase domain. Phosphorylation-dependent binding of the PBD to its ligands releases the kinase domain, while simultaneously localizing Polo-like kinases to specific subcellular structures. These observations suggest two different models for how the PBD integrates signals arising from other mitotic kinases to target the activated kinase towards distinct substrates. The recent X-ray crystal structures of the PBD provide insights into the structural basis for PBD function and kinase regulation. Molecular modelling of the structure of the isolated kinase domain reveals a potential basis for motif-dependent substrate specificity.

Cell Cycle Proteins↗
PubMed2004

Inhibition of TATA binding protein dimerization by RNA polymerase III transcription initiation factor Brf1.

The Brf1 subunit of TFIIIB plays an important role in recruiting the TATA-binding protein (TBP) to the up-stream region of genes transcribed by RNA polymerase III. When TBP is not bound to promoters, it sequesters its DNA binding domain through dimerization. Promoter assembly factors therefore might be required to dissociate TBP into productively binding monomers. Here we show that Saccharomyces cerevisiae Brf1 induces TBP dimers to dissociate. The high affinity TBP binding domain of Brf1 is not sufficient to promote TBP dimer dissociation but in addition requires the TFIIB homology domain of Brf1. A model is proposed to explain how two distinct functional domains of Brf1 work in concert to dissociate TBP into monomers.

Alleles↗
PubMed2004

Structure and mechanism of BRCA1 BRCT domain recognition of phosphorylated BACH1 with implications for cancer.

Germline mutations in the BRCA1 tumor suppressor gene often result in a significant increase in susceptibility to breast and ovarian cancers. Although the molecular basis of their effects remains largely obscure, many mutations are known to target the highly conserved C-terminal BRCT repeats that function as a phosphoserine/phosphothreonine-binding module. We report the X-ray crystal structure at a resolution of 1.85 A of the BRCA1 tandem BRCT domains in complex with a phosphorylated peptide representing the minimal interacting region of the DEAH-box helicase BACH1. The structure reveals the determinants of this novel class of BRCA1 binding events. We show that a subset of disease-linked mutations act through specific disruption of phospho-dependent BRCA1 interactions rather than through gross structural perturbation of the tandem BRCT domains.

BRCA1 Protein↗
PubMed2003

BRCT repeats as phosphopeptide-binding modules involved in protein targeting.

We used a proteomic approach to identify phosphopeptide-binding modules mediating signal transduction events in the DNA damage response pathway. Using a library of partially degenerate phosphopeptides, we identified tandem BRCT (BRCA1 carboxyl-terminal) domains in PTIP (Pax transactivation domain-interacting protein) and in BRCA1 as phosphoserine- or phosphothreonine-specific binding modules that recognize substrates phosphorylated by the kinases ATM (ataxia telangiectasia-mutated) and ATR (ataxia telangiectasia- and RAD3-related) in response to gamma-irradiation. PTIP tandem BRCT domains are responsible for phosphorylation-dependent protein localization into 53BP1- and phospho-H2AX (gamma-H2AX)-containing nuclear foci, a marker of DNA damage. These findings provide a molecular basis for BRCT domain function in the DNA damage response and may help to explain why the BRCA1 BRCT domain mutation Met1775 --> Arg, which fails to bind phosphopeptides, predisposes women to breast and ovarian cancer.

Amino Acid Motifs↗