Dataset Information

Regulation of synaptic Pumilio function by an aggregation-prone domain.

ABSTRACT: We identified Pumilio (Pum), a Drosophila translational repressor, in a computational search for metazoan proteins whose activities might be regulated by assembly into ordered aggregates. The search algorithm was based on evolutionary sequence conservation patterns observed for yeast prion proteins, which contain aggregation-prone glutamine/asparagine (Q/N)-rich domains attached to functional domains of normal amino acid composition. We examined aggregation of Pum and its nematode ortholog PUF-9 by expression in yeast. A domain of Pum containing the Q/N-rich sequence, denoted as NQ1, the entire Pum N terminus, and the complete PUF-9 protein localize to macroscopic aggregates (foci) in yeast. NQ1 and PUF-9 can generate the yeast Pin+ trait, which is transmitted by a heritable aggregate. NQ1 also assembles into amyloid fibrils in vitro. In Drosophila, Pum regulates postsynaptic translation at neuromuscular junctions (NMJs). To assess whether NQ1 affects synaptic Pum activity in vivo, we expressed it in muscles. We found that it negatively regulates endogenous Pum, producing gene dosage-dependent pum loss-of-function NMJ phenotypes. NQ1 coexpression also suppresses lethality and NMJ phenotypes caused by overexpression of Pum in muscles. The Q/N block of NQ1 is required for these phenotypic effects. Negative regulation of Pum by NQ1 might be explained by formation of inactive aggregates, but we have been unable to demonstrate that NQ1 aggregates in Drosophila. NQ1 could also regulate Pum by a "dominant-negative" effect, in which it would block Q/N-mediated interactions of Pum with itself or with cofactors required for translational repression.

SUBMITTER: Salazar AM

PROVIDER: S-EPMC2847508 | biostudies-literature | 2010 Jan

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Regulation of synaptic Pumilio function by an aggregation-prone domain.

Salazar Anna M AM Silverman Edward J EJ Menon Kaushiki P KP Zinn Kai K

The Journal of neuroscience : the official journal of the Society for Neuroscience 20100101 2

We identified Pumilio (Pum), a Drosophila translational repressor, in a computational search for metazoan proteins whose activities might be regulated by assembly into ordered aggregates. The search algorithm was based on evolutionary sequence conservation patterns observed for yeast prion proteins, which contain aggregation-prone glutamine/asparagine (Q/N)-rich domains attached to functional domains of normal amino acid composition. We examined aggregation of Pum and its nematode ortholog PUF-9 ...[more]

PMID: 20071514

Similar Datasets

Project description:BackgroundThe eye lens crystallins are highly soluble proteins that are required to last the lifespan of an organism due to low protein turnover in the lens. Crystallin aggregation leads to formation of light-scattering aggregates known as cataract. The G18V mutation of human ?S-crystallin (?S-G18V), which is associated with childhood-onset cataract, causes structural changes throughout the N-terminal domain and increases aggregation propensity. The holdase chaperone protein ?B-crystallin does not interact with wild-type ?S-crystallin, but does bind its G18V variant. The specific molecular determinants of ?B-crystallin binding to client proteins is incompletely charcterized. Here, a new variant of ?S, ?S-G18A, was created to test the limits of ?B-crystallin selectivity.MethodsMolecular dynamics simulations were used to investigate the structure and dynamics of ?S-G18A. The overall fold of ?S-G18A was assessed by circular dichroism (CD) spectroscopy and intrinsic tryptophan fluorescence. Its thermal unfolding temperature and aggregation propensity were characterized by CD and DLS, respectively. Solution-state NMR was used to characterize interactions between ?B-crystallin and ?S-G18A.Results?S-G18A exhibits minimal structural changes, but has compromised thermal stability relative to ?S-WT. The placement of alanine, rather than valine, at this highly conserved glycine position produces minor changes in hydrophobic surface exposure. However, human ?B-crystallin does not bind the G18A variant, in contrast to previous observations for ?S-G18V, which aggregates at physiological temperature.Conclusions?B-crystallin is capable of distinguishing between aggregation-prone and function-preserving variants, and recognizing the transient unfolding or minor conformers that lead to aggregation in the disease-related variant.General significanceHuman ?B-crystallin distinguishes between highly similar variants of a structural crystallin, binding the cataract-related ?S-G18V variant, but not the function-preserving ?S-G18A variant, which is monomeric at physiological temperature.

Dataset Information

Regulation of synaptic Pumilio function by an aggregation-prone domain.

Publications

Regulation of synaptic Pumilio function by an aggregation-prone domain.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets