Biology subjects

Anderson, J. W.

Publications and source records attributed to Anderson, J. W..

2 recordsLinked to original sources

bioRxiv2023

Patterns and drivers of pollen co-transport networks vary across pollinator groups

Pollen transport is an understudied process with consequences for plant reproductive success and floral evolution. Recently, pollinator bodies have been described as pollen competition arenas, with implications for plant community assembly. However, the identity, strength, and diversity of pollen competitive interactions and how they vary across pollinator groups is unknown. Evaluating patterns and drivers of the pollen competition landscape across different pollinator groups is central to further our understanding of plant coexistence mechanisms. Here, we integrate information on insect pollen loads with network analyses to uncover novel pollen co-transport networks and how these vary across pollinators. We evaluate differences in pollen load size, diversity and their phenological and phylogenetic attributes among insect groups and how these relate to body size and sex. Pollen co-transport networks revealed differences in the number and identity of competitors that pollen species encounter across pollinator groups. These networks were highly modular, with groups of pollen species interacting more often on pollinator bodies. Pollen load size and richness were shaped by bee size and sex. Sex also influenced the pollen phylogenetical diversity. Pollinators can impose vastly different competitive landscapes during pollen transport, with so far unknown consequences for plant reproductive success, floral evolution and community assembly.

ecology↗

bioRxiv2023

Conformation Selection by ATP-competitive Inhibitors and Allosteric Communication in ERK2

Activation of the extracellular signal regulated kinase-2 (ERK2) by phosphorylation has been shown to involve changes in protein dynamics, as determined by hydrogen-deuterium exchange mass spectrometry (HDX-MS) and NMR relaxation dispersion measurements. These can be described by a global exchange between two conformational states of the active kinase, named "L" and "R", where R is associated with a catalytically productive ATP-binding mode. An ATP-competitive ERK1/2 inhibitor, Vertex-11e, has properties of conformation selection for the R-state, revealing movements of the activation loop that are allosterically coupled to the kinase active site. However, the features of inhibitors important for R-state selection are unknown. Here we survey a panel of ATP-competitive ERK inhibitors using HDX-MS and NMR and identify 14 new molecules with properties of R-state selection. They reveal effects propagated to distal regions in the P+1 and helix F segments surrounding the activation loop, as well as helix L16. Crystal structures of inhibitor complexes with ERK2 reveal systematic shifts in the Gly loop and helix C, mediated by a Tyr-Tyr ring stacking interaction and the conserved Lys-Glu salt bridge. The findings suggest a model for the R-state involving small movements in the N-lobe that promote compactness within the kinase active site and alter mobility surrounding the activation loop. Such properties of conformation selection might be exploited to modulate the protein docking interface used by ERK substrates and effectors.

biochemistry↗