Phosphoinositide kinase signaling controls ER-PM cross-talk

Membrane lipid dynamics must be precisely regulated for normal cellular function, and disruptions in lipid homeostasis are linked to the progression of several diseases. However, little is known about the sensory mechanisms for detecting membrane composition and how lipid metabolism is regulated in response to membrane stress. We find that phosphoinositide (PI) kinase signaling controls a conserved PDK-TORC2-Akt signaling cascade as part of a homeostasis network that allows the endoplasmic reticulum (ER) to modulate essential responses, including Ca(2+)-regulated lipid biogenesis, upon plasma membrane (PM) stress. Furthermore, loss of ER-PM junctions impairs this protective response, leading to PM integrity defects upon heat stress. Thus PI kinase-mediated ER-PM cross-talk comprises a regulatory system that ensures cellular integrity under membrane stress conditions

Mdm1/Snx13 is a novel ER-endolysosomal interorganelle tethering protein

Although endolysosomal trafficking is well defined, how it is regulated and coordinates with cellular metabolism is unclear. To identify genes governing endolysosomal dynamics, we conducted a global fluorescence-based screen to reveal endomembrane effector genes. Screening implicated Phox (PX) domain-containing protein Mdm1 in endomembrane dynamics. Surprisingly, we demonstrate that Mdm1 is a novel interorganelle tethering protein that localizes to endoplasmic reticulum (ER)-vacuole/lysosome membrane contact sites (MCSs). We show that Mdm1 is ER anchored and contacts the vacuole surface in trans via its lipid-binding PX domain. Strikingly, overexpression of Mdm1 induced ER-vacuole hypertethering, underscoring its role as an interorganelle tether. We also show that Mdm1 and its paralogue Ydr179w-a (named Nvj3 in this study) localize to ER-vacuole MCSs independently of established tether Nvj1. Finally, we find that Mdm1 truncations analogous to neurological disease-associated SNX14 alleles fail to tether the ER and vacuole and perturb sphingolipid metabolism. Our work suggests that human Mdm1 homologues may play previously unappreciated roles in interorganelle communication and lipid metabolism

TRY plant trait database - enhanced coverage and open access

Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives

Restoring brain function after stroke - bridging the gap between animals and humans

Stroke is the leading cause of complex adult disability in the world. Recovery from stroke is often incomplete, which leaves many people dependent on others for their care. The improvement of long-term outcomes should, therefore, be a clinical and research priority. As a result of advances in our understanding of the biological mechanisms involved in recovery and repair after stroke, therapeutic opportunities to promote recovery through manipulation of poststroke plasticity have never been greater. This work has almost exclusively been carried out in preclinical animal models of stroke with little translation into human studies. The challenge ahead is to develop a mechanistic understanding of recovery from stroke in humans. Advances in neuroimaging techniques now enable us to reconcile behavioural accounts of recovery with molecular and cellular changes. Consequently, clinical trials can be designed in a stratified manner that takes into account when an intervention should be delivered and who is most likely to benefit. This approach is expected to lead to a substantial change in how restorative therapeutic strategies are delivered in patients after stroke

TRY plant trait database - enhanced coverage and open access

Plant traits—the morphological, anatomical, physiological, biochemical and phenological characteristics of plants—determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait‐based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits—almost complete coverage for ‘plant growth form’. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait–environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives

Coatomer is essential for retrieval of dilysine-tagged proteins to the endoplasmic reticulum.

International audienceDilysine motifs in cytoplasmic domains of transmembrane proteins are signals for their continuous retrieval from the Golgi back to the endoplasmic reticulum (ER). We describe a system to assess retrieval to the ER in yeast cells making use of a dilysine-tagged Ste2 protein. Whereas retrieval was unaffected in most sec mutants tested (sec7, sec12, sec13, sec16, sec17, sec18, sec19, sec22, and sec23), a defect in retrieval was observed in previously characterized coatomer mutants (sec21-1, sec27-1), as well as in newly isolated retrieval mutants (sec21-2, ret1-1). RET1 was cloned by complementation and found to encode the alpha subunit of coatomer. While temperature-sensitive for growth, the newly isolated coatomer mutants exhibited a very modest defect in secretion at the nonpermissive temperature. Coatomer from beta'-COP (sec27-1) and alpha-COP (ret1-1) mutants, but not from gamma-COP (sec21) mutants, had lost the ability to bind dilysine motifs in vitro. Together, these results suggest that coatomer plays an essential role in retrograde Golgi-to-ER transport and retrieval of dilysine-tagged proteins back to the ER.Dilysine motifs in cytoplasmic domains of transmembrane proteins are signals for their continuous retrieval from the Golgi back to the endoplasmic reticulum (ER). We describe a system to assess retrieval to the ER in yeast cells making use of a dilysine-tagged Ste2 protein. Whereas retrieval was unaffected in most sec mutants tested (sec7, sec12, sec13, sec16, sec17, sec18, sec19, sec22, and sec23), a defect in retrieval was observed in previously characterized coatomer mutants (sec21-1, sec27-1), as well as in newly isolated retrieval mutants (sec21-2, ret1-1). RET1 was cloned by complementation and found to encode the alpha subunit of coatomer. While temperature-sensitive for growth, the newly isolated coatomer mutants exhibited a very modest defect in secretion at the nonpermissive temperature. Coatomer from beta'-COP (sec27-1) and alpha-COP (ret1-1) mutants, but not from gamma-COP (sec21) mutants, had lost the ability to bind dilysine motifs in vitro. Together, these results suggest that coatomer plays an essential role in retrograde Golgi-to-ER transport and retrieval of dilysine-tagged proteins back to the ER