Jan K Rainey

Dalhousie University | Dal · Department of Biochemistry and Molecular Biology

Spider silks are renowned for their mechanical properties. The notably tough Argiope trifasciata aciniform silk is spun from a protein predominantly comprising a series of identical 200 residue units (“W units”). In solution, each W unit has a globular 5‐helix domain connected to its neighbors by intrinsically disordered linkers while the fiber con...

Pyriform (or piriform) silk is a fibrous spider silk used in a composite material to attach web silks to substrates and disparate silk types together. Argiope argentata pyriform silk is formed from a protein with a central repetitive region consisting of a 234-amino acid unit (the “Py unit”) repeated 21 times. We have previously shown that the Py u...

Spider silks are natural protein-based biomaterials which are renowned for their mechanical properties and hold great promise for applications ranging from high-performance textiles to regenerative medicine. While some spiders can produce several different types of silks, most spider silk types – including pyriform and aciniform silks – are relativ...

Proteins are biomolecules with potential applications in agriculture, food sciences, pharmaceutics, biotechnology, and drug delivery. Interactions of hydrophilic and biocompatible polymers with proteins may impart proteolytic stability, improving the therapeutic effects of biomolecules and also acting as excipients for the prolonged storage of prot...

Energy and resource intensive mechanical and chemical pretreatment along with the use of hazardous chemicals are major bottlenecks in widespread lignocellulosic biomass utilization. Herein, the study investigated different pretreatment methods on spruce wood namely supercritical CO2 (scCO2) pretreatment, ultrasound-assisted alkaline pretreatment, a...

Enzymes have great potential in bioprocess engineering due to their green and mild reaction conditions. However, there are challenges to their application, such as enzyme extraction and purification costs, enzyme recovery, and long reaction time. Enzymatic reaction rate enhancement and enzyme immobilization have the potential to overcome some of th...

Orb-weaving spiders produce up to seven silk types, each with distinct biological roles, protein compositions, and mechanics. Pyriform (or piriform) silk is composed of pyriform spidroin 1 (PySp1) and is the fibrillar component of attachment discs that attach webs to substrates and to each other. Here, we characterize the 234-residue repeat unit (t...

Polymeric drug releasing systems have numerous applications for the treatment of chronic diseases and traumatic injuries. In this study, a simple, cost-effective, and scalable method for dry spinning of crosslinked polyvinyl alcohol (PVA) fibers is presented. This method utilizes an entangled solution of PVA to form liquid bridges that are drawn in...

The human MDM2 protein regulates the tumor suppressor protein p53 by restricting its transcriptional activity and by promoting p53 degradation. MDM2 is ubiquitously expressed, with its overexpression implicated in many forms of cancer. The inhibitory effects of MDM2 on p53 have been shown to involve its N-terminal p53-binding domain and its C-termi...

Spider silks have outstanding potential as biomaterials due to their sought‐after mechanical properties and low immunogenicity. The toughest spider silk is aciniform silk, which is used by spiders to wrap prey and produce egg sacs. A variety of recombinant aciniform silk constructs are now been developed, including hybrid silks with domains from mu...

Type I collagen is the most abundant protein in the human body and is known to play important roles in numerous biological processes including tissue morphogenesis and wound healing. As such, it is one of the most frequently used substrates for cell culture, and there have been considerable efforts to develop collagen-based cell culture substrates...

The tumor suppressor protein p53 governs many cellular pathways to control genome integrity, metabolic homeostasis, and cell viability. The critical roles of p53 highlight the importance of proper control over p53 in maintaining normal cellular function, with the negative regulators MDM2 and MDMX playing central roles in regulating p53 activity. Th...

The human MDMX protein, also known as MDM4, plays a pivotal role in regulating the activity of the tumor suppressor protein p53 by restricting p53 transcriptional activity and stimulating the E3 ubiquitin ligase activity of another key regulatory protein, MDM2, to promote p53 degradation. MDMX is ubiquitously expressed in most tissue types and over...

KIT, a type III tyrosine kinase receptor, plays a crucial role in haematopoietic development. The KIT receptor forms a dimer after ligand binding; this activates tyrosine kinase activity leading to downstream signal transduction. The D816V KIT mutation is extensively implicated in haematological malignancies, including mastocytosis and leukaemia. K...

In this study, we report that host defense protein-derived ten amino acid long disulfide-linked peptides self-assemble in the form of β-sheets and β-turns, and exhibit concentration-dependent self-assembly in the form of nanospheres, termed as disulfide linked nanospheres (DSNs). As expected, bare DSNs are prone to aggregation in ionic solutions an...

Elabela (ELA; also called Apela and Toddler) is one of the recently discovered ligand among the two endogenous peptide ligands (Apelin and Elabela) of the apelin receptor (APLNR, also known as APJ). Elabela-induced signaling plays a crucial role in diverse biological processes, including formation of the embryonic cardiovascular system and early pl...

Nuclear magnetic resonance (NMR) spectroscopy allows the determination of atomic-level information on intermolecular interactions, molecular structure, and molecular dynamics in the cellular environment. This may be broadly divided into studies focused on obtaining detailed molecular information in the intracellular context (“in-cell”) or those foc...

The apelin receptor (APLNR) is a class A (rhodopsin-like) G-protein coupled receptor with a wide distribution throughout the human body. Activation of the apelin/APLNR system regulates AMPK/PI3K/AKT/mTOR and RAF/ERK1/2 mediated signaling pathways. APLNR activation orchestrates several downstream signaling cascades, which play diverse roles in physi...

Studying prostate cancer cells embedded in hyaluronic acid hydrogels provides insight on how metastatic cells might behave in diffusion-limited tissue microenvironments.

Pyriform silk is a critically important fiber in spider web construction. It functions in a glue-coated attachment disc to form junctions in spider webs, connecting the web to disparate materials. Despite the biological importance of this silk, both natural and recombinant pyriform silk have yet to be structurally or mechanically characterized. In...

Phosphorylation events modify bacterial and archaeal proteomes, imparting cells with rapid and reversible responses to specific environmental stimuli or niches. Phosphorylated proteins are generally modified at one or more serine, threonine, or tyrosine residues. Within the last ten years, increasing numbers of global phosphoproteomic surveys of pr...

G-protein coupled receptors (GPCRs) typically have an amphipathic helix ("helix 8") immediately C-terminal to the transmembrane helical bundle. To date, a number of functional roles have been associated with GPCR helix 8 segments, but structure-function analysis for this region remains limited. Here, we examine helix 8 of the apelin receptor (AR or...

To probe ligand-receptor binding at the atomic-level, a frequent approach involves multidimensional nuclear magnetic resonance (NMR) spectroscopy experiments relying on 13C- and/or 15N-enrichment alongside 1H. Alternatively, the lack of fluorine in biomolecules may be exploited through specific incorporation of 19F nuclei into a sample. The 19F nuc...

Apelin is a peptide hormone that binds to a class A GPCR (the apelin receptor/APJ) to regulate various bodily systems. Upon signal peptide removal, the resulting 55-residue isoform, proapelin/apelin-55, can be further processed to 36-, 17-, or 13-residue isoforms with length-dependent pharmacological properties. Processing was initially proposed to...

In article number 1805294, Xiang‐Qin Liu, Jan K. Rainey, and co‐workers demonstrate that improved self‐assembled silk protein nanoparticle monodispersity in the concentrated solubilized spinning dope state correlates with dramatically improved wet‐spun recombinant aciniform silk fiber mechanical behavior. The nature and dispersity of self‐assembly...

Spider silks are desirable materials with mechanical properties superior to most synthetic materials coupled with biodegradability and biocompatibility. In order to replicate natural silk properties using recombinant spider silk proteins (spidroins) and wet‐spinning methods, the focus to date has typically been on modifying protein sequence, protei...

Apelin peptides are cognate ligands for the apelin receptor, a G-protein-coupled receptor (GPCR). The apelinergic system plays critical roles in wide-ranging physiological activities including function and development of the central nervous and cardiovascular systems. Apelin is found in 13–55 residue isoforms in vivo, all of which share the C-termi...

Sodium 4,4-dimethyl-4-silapentane-1-sulfonate (DSS) is the most widely accepted internal standard for protein NMR studies in aqueous conditions. Since its introduction as a reference standard, however, concerns have been raised surrounding its propensity to interact with biological molecules through electrostatic and hydrophobic interactions. While...

F NMR spectroscopy of protein isoform mixtures containing assorted combinations of fluorotryptophan isomers at each Trp was employed to compare the binding of two peptide ligands to a ¹⁹F-labeled G-protein-coupled receptor fragment in micellar solution. Protein mixtures with assorted flurotryptophan labels are straightforward to produce and study,...

The strategy of applying fluorine NMR to characterize ligand binding to a membrane protein prepared with mixtures of tryptophans substituted with F at different positions on the indole ring was tested. The ¹⁹F NMR behavior of 4-, 5-, 6-, and 7-fluorotryptophan were directly compared as a function of both micellar environment and fragment size for t...

Apelin and apela (ELABELA/ELA/Toddler) are two peptide ligands for a class A G-protein-coupled receptor named the apelin receptor (AR/APJ/APLNR). Ligand-AR interactions have been implicated in regulation of the adipoinsular axis, cardiovascular system, and central nervous system alongside pathological processes. Each ligand may be processed into a...

Apelin is one of two peptide hormones that activate the apelin receptor (AR or APJ) to regulate the cardiovascular system, central nervous system, and adipoinsular axis. Here, we apply circular dichroism (CD) spectropolarimetry and nuclear magnetic resonance (NMR) spectroscopy to characterize the potential membrane binding by the two longest bioact...

The Na+/H+ exchanger of the plasma membrane of S. pombe (SpNHE1) removes intracellular sodium in exchange for an extracellular proton. We examined the structure and functional role of amino acids 360–393 of putative transmembrane (TM) segment XI of SpNHE1. Structural analysis suggested that it had a helical propensity over amino acids 360–368, an e...

Spider aciniform (or wrapping) silk is the toughest of the seven types of spider silks/glue due to a combination of high elasticity and strength. Like most spider silk proteins (spidroins), aciniform spidroin (AcSp1) has a large core repetitive domain flanked by relatively short N- and C-terminal non-repetitive domains (the NTD and CTD, respectivel...

Detergent micelles are frequently employed as membrane mimetics for solution-state membrane protein nuclear magnetic resonance (NMR) spectroscopy. Here, we compare topology, structure, ps-ns timescale dynamics, and hydrodynamics of a model protein with one transmembrane (TM) segment (residues 1-55 of the apelin receptor, APJ, a G-protein-coupled re...

Background: Apelin is a peptide ligand for a class A G-protein coupled receptor called the apelin receptor (AR or APJ) that regulates angiogenesis, the adipoinsular axis, and cardiovascular functions. Apelin has been shown to be bioactive as 13, 17, and 36 amino acid isoforms, C-terminal fragments of the putatively inactive 55-residue proprotein (...

Bioactive apelin peptide forms ranging in length from 12 to 55 amino acids bind to and activate the apelin receptor (AR or APJ), a class A G-protein coupled receptor. Apelin-12, -17, and -36 isoforms, named according to length, with an additional N-terminal cysteine residue allowed for regiospecific and efficient conjugation of pyrene-maleimide. Th...

Apela (also referred to as ELABELA and toddler) is a peptide hormone that activates the apelin receptor (AR or APJ) to regulate cardiovascular system development and function. Here, we report the first biophysical characterization of three apela isoforms, apela-54, -32, and -11, alongside a monomeric C1S-apela-11 mutant, using circular dichroism (C...

G protein-coupled receptors (GPCRs) play an important role in drug therapy, and represent one of the largest families of drug targets. The angiotensin II type 1 receptor (AT1R) is notable as it has a central role in the treatment of cardiovascular disease. Blockade of AT1R signaling has been shown to alleviate hypertension and improve outcomes in p...

Impaired adenosine homeostasis has been associated with numerous human diseases. Lysosomes are referred to as the cellular recycling centers which generate adenosine by breaking down nucleic acids or ATP. Recent studies have suggested that lysosomal adenosine overload causes lysosome defects which phenocopy patients with mutations in TRPML1, a lyso...

The Monday morning session on lipid metabolism, sponsored by VWR and organized by Dr. Aarnoud van der Spoel, started off with a presentation by Dr. Tobias Hartmann, from Saarland University, Germany, who outlined the close inter-relationship between membrane lipids and amyloid precursor protein (APP) cleavage. A strong influence of gangliosides and...

Spider aciniform (wrapping) silk is a remarkable fibrillar biomaterial with outstanding mechanical properties. It is a modular protein consisting, in Argiope trifasciata, of a core repetitive domain of 200 amino acid units (W units). In solution, the W units comprise a globular folded core, with five α-helices, and disordered tails that are linked...

Spider silks are outstanding biomaterials with mechanical properties that outperform synthetic materials. Of the six fibrillar spider silks, aciniform (or wrapping) silk is the toughest through a unique combination of strength and extensibility. In this study, a wet-spinning method for recombinant Argiope trifasciata aciniform spidroin (AcSp1) is i...

Aciniform silk protein (AcSp1) is the primary component of wrapping silk, the toughest of the spider silks due to combined high tensile strength and extensibility. Argiope trifasciata AcSp1 contains a core repetitive domain with at least 14 homogeneous 200-amino acid units ("W" units). Upon fibrillogenesis, AcSp1 converts from an α-helix-rich solub...

Membrane proteins are still heavily under-represented in the protein data bank (PDB), owing to multiple bottlenecks. The typical low abundance of membrane proteins in their natural hosts makes it necessary to overexpress these proteins either in heterologous systems or through in vitro translation/cell-free expression. Heterologous expression of pr...

Spiders store spidroins in their silk glands as high concentration aqueous solutions, spinning these dopes into fibres with outstanding mechanical properties. Aciniform (or wrapping) silk is the toughest spider silk and is devoid of the short amino acid sequence motifs characteristic of the other spidroins. Using solution-state NMR spectroscopy, we...

Pore formation is the most energy-demanding step during virus-induced membrane fusion, where high curvature of the fusion pore rim increases the spacing between lipid headgroups, exposing the hydrophobic interior of the membrane to water. How protein fusogens breach this thermodynamic barrier to pore formation is unclear. We identified a novel fusi...

Deregulation of cellular polarity proteins and their associated complexes lead to changes in cell migration and proliferation. The nitric oxide synthase 1 adaptor protein (NOS1AP) associates with the tumor suppressor protein scribble to control cell migration and oncogenic transformation. However, how NOS1AP is linked to the cell signaling events t...

The physicochemical properties of soft nanoparticles, most notably size, morphology and ligand interactions, typically depend upon the solution environment in which they are suspended. Comprehensive characterization in a given environment is therefore essential. We have employed high-resolution solution nuclear magnetic resonance (NMR) spectroscopy...

Of the 750 GPCRs said to be expressed in humans, only approximately 20 individual high-resolution crystal structures are available for human GPCRs. While GPCR oligomerization is a common occurrence, very few groups have had success in crystallizing these structures. Given the fact that the pharmacology of these entities has been shown to diverge fr...

Apelin is a peptide hormone that activates the class A G-protein coupled apelin receptor. Apelin is found in several bioactive isoforms in the body, ranging from 12 to 55 amino acids in length. Apelin-17 has previously been shown to bind to micelles of anionic detergents, which implies that apelin may interact with cell membranes prior to receptor...

The reovirus p10 fusion-associated small transmembrane (FAST) proteins are the smallest known membrane fusion proteins, and evolved specifically to mediate cell-cell, rather than virus-cell, membrane fusion. The 36-40-residue ectodomains of avian reovirus (ARV) and Nelson Bay reovirus (NBV) p10 contain an essential intramolecular disulfide bond req...

The apelin receptor (AR or APJ) is a class A (rhodopsin-like) G-protein-coupled receptor with wide distribution throughout the human body. Activation of the AR by its cognate peptide ligand, apelin, induces diverse physiological effects including vasoconstriction and dilation, strengthening of heart muscle contractility, angiogenesis, and regulatio...

G-protein coupled receptors (GPCRs) are inherently dynamic membrane protein modulators of various important cellular signaling cascades. The apelin receptor (AR or APJ) is a class A GPCR involved in numerous physiological processes, implicated in angiogenesis during tumour formation and as a CD4 co-receptor for entry of human immunodeficiency virus...

Apolipoprotein (apo) B100 is a 550 kDa hydrophobic glycoprotein that forms the structural backbone for the assembly of triglyceride-rich lipoproteins. ApoB100 circulates bound to the same lipoprotein particle on which it is synthesized (i.e. it is non-exchangeable) until the lipoprotein is cleared from the plasma via receptor-mediated uptake. The p...

The peptide hormone apelin is translated as a 77-residue preproprotein, truncated to the 55-residue proapelin and, subsequently, to 13-36-residue bioactive isoforms named apelin-13 to -36. Proapelin is hypothesized to be cleaved to apelin-36 and then to the shorter isoforms. However, neither the mechanism of proapelin processing nor the endoproteas...