Search PubMed⌕ Search

Biomedical subjects

J Lally

Publications and source records attributed to J Lally.

At least 19 recordsLinked to original sources
PubMed2001

Solution structure and interaction surface of the C-terminal domain from p47: a major p97-cofactor involved in SNARE disassembly.

p47 is the major protein identified in complex with the cytosolic AAA ATPase p97. It functions as an essential cofactor of p97-regulated membrane fusion, which has been suggested to disassemble t-t-SNARE complexes and prepare them for further rounds of membrane fusion. Here, we report the high-resolution NMR structure of the C-terminal domain from p47. It comprises a UBX domain and a 13 residue long structured N-terminal extension. The UBX domain adopts a characteristic ubiquitin fold with a betabetaalphabetabetaalphabeta secondary structure arrangement. Three hydrophobic residues from the N-terminal extension pack closely against a cleft in the UBX domain. We also identify, for the first time, the p97 interaction surface using NMR chemical shift perturbation studies.

Adenosine Triphosphatases↗
PubMed2000

Structure of the AAA ATPase p97.

p97, an abundant hexameric ATPase of the AAA family, is involved in homotypic membrane fusion. It is thought to disassemble SNARE complexes formed during the process of membrane fusion. Here, we report two structures: a crystal structure of the N-terminal and D1 ATPase domains of murine p97 at 2.9 A resolution, and a cryoelectron microscopy structure of full-length rat p97 at 18 A resolution. Together, these structures show that the D1 and D2 hexamers pack in a tail-to-tail arrangement, and that the N domain is flexible. A comparison with NSF D2 (ATP complex) reveals possible conformational changes induced by ATP hydrolysis. Given the D1 and D2 packing arrangement, we propose a ratchet mechanism for p97 during its ATP hydrolysis cycle.

Adenosine Diphosphate↗
PubMed1996

20S human proteasomes bind with a specific orientation to lipid monolayers in vitro.

20S Proteasomes are non-lysosomal, high molecular weight proteinases implicated in the degradation of misfolded proteins and several short-lived regulatory proteins. They have a well established role, as the core of the 26S proteasome complex, in the ubiquitin-dependent proteolytic pathway and in antigen processing. While correctly folded proteins are not degraded by the 20S proteasome, unfolding, for example by oxidation, may render them degradable. The 20S proteasome is a 700-kDa cylindrical particle, composed of 14 subunits of molecular masses 20-35 kDa. There is evidence that 20S proteasomes are in close proximity to or associate with the endoplasmic reticulum and nuclear and plasma membranes in vivo. To better understand the lipid association of 20S proteasomes in vitro, we used a lipid monolayer system as a simple model system for biological membranes. The structure and orientation of the monolayer lipid bound 20S proteasomes has been determined by electron microscopy. 20S proteasomes associated in an "end-on' configuration specifically on PI lipid monolayers forming large arrays, with their channels opposite the lipid headgroups. On ER and Golgi lipid films 20S proteasomes were oriented in the same way as on the PI lipid film but were monodisperse. Protein molecules were randomly oriented in the presence of PA, PG, PS, PC and mitochondrial lipid monolayers. We show that 20S proteasomes bind to phospholipids in vitro in a preferred orientation which places the proteasome channel perpendicular to the membrane.

Cell Membrane↗
PubMed1995

The solution structure of the RING finger domain from the acute promyelocytic leukaemia proto-oncoprotein PML.

Acute promyelocytic leukaemia (APL) has been ascribed to a chromosomal translocation event which results in a fusion protein comprising the PML protein and the retinoic acid receptor alpha. PML is normally a component of a nuclear multiprotein complex (termed ND10, Kr bodies, nuclear bodies, PML oncogenic domains or PODs) which is disrupted in the APL disease state. PML contains a number of characterized motifs including a Zn2+ binding domain called the RING or C3HC4 finger. Here we describe the solution structure of the PML RING finger as solved by 1H NMR methods at physiological pH with r.m.s. deviations for backbone atoms of 0.88 and 1.39 A for all atoms. Additional biophysical studies including CD and optical spectroscopy, show that the PML RING finger requires Zn2+ for autonomous folding and that cysteines are used in metal ligation. A comparison of the structure with the previously solved equine herpes virus IE110 RING finger, shows significant differences suggesting that the RING motif is structurally diverse. The role of the RING domain in PML nuclear body formation was tested in vivo, by using site-directed mutagenesis and immunofluorescence on transiently transfected NIH 3T3 cells. Independently mutating two pairs of cysteines in each of the Zn2+ binding sites prevents PML nuclear body formation, suggesting that a fully folded RING domain is necessary for this process. These results suggest that the PML RING domain is probably involved in protein-protein interactions, a feature which may be common to other RING finger domains.

Amino Acid Sequence↗
PubMed1988

Morphological studies of an ion-dependent perinuclear cataract model.

The perinuclear region of the rabbit lens is susceptible to alterations in the ionic composition of incubation medium. Rabbit lenses and a comparable cell type, red blood cells, were stressed during ex vivo incubations in isotonic modified Earle's medium with 131 mM NaCl replaced by either 232 mM sucrose or 131 mM choline chloride at pH 7.2 (normal) or 9.2. Our parallel NMR study revealed that these experimental media maintain normal intracellular pH and phosphorus metabolite levels. The present study demonstrates that lens transparency, normal fiber cell ultrastructure and volume were maintained in either sodium chloride or choline chloride containing media at normal or elevated pH. Similarly, normal morphology, mean cell volume (MCV) and mean cell hemoglobin concentration (MCHC), 86.8 +/- 0.03 micron 3 and 33.2 +/- 1.0 g dl-1, respectively, were maintained in red blood cells in either sodium chloride or choline chloride containing media. In sodium chloride deficient media at both normal and elevated pH the lens developed a nuclear cataract based on slit-lamp examination; however, SEM examination showed that fiber cell morphological abnormalities were confined to a narrow band, 50 micron wide, in the perinuclear region of the transition zone. Damage consisted of ruptured cell membranes and an absence of identifiable interdigitations with the combination of sodium chloride deficiency and elevated pH. The major abnormality produced during incubation in sodium chloride deficient medium at normal pH was the presence of numerous smooth-surfaced cellular protrusions along the vertices of the perinuclear fiber cells. In addition, the sodium chloride deficient medium, pH 9.2, produced a volume loss both in the lens and RBC (4.5 +/- 1.5% and 5.6 +/- 1.1%, respectively). The sodium chloride deficient medium, pH 7.4, produced no volume loss in the lens or red blood cells (MCV 86.0 +/- 0.05 micron 3). Further studies indicated that the cataract induced by sodium chloride deficiency (pH 9.2) is irreversible. The mechanism for perinuclear opacification due to ion deficiency remains to be elucidated.

Animals↗
PubMed1979

The Canberra mental health survey: further analysis of the adult sample.

Secondary analysis of the Canberra Mental Health Survey (adult sample) extends the results of earlier analysis. New relationships between independent and dependent variables are revealed. Marital status previously not associated with mental health proves important when sex and socioeconomic status are controlled. Participation in organizations is strongly associated with social variables and mental health adjustment, suggesting explanations of mental health in relation to social support.

Adult↗