van Haren, M. | bioRxiv Science

bioRxiv2024

Controlling interfacial protein adsorption, desorption and aggregation in biomolecular condensates

The aggregation of amyloidogenic proteins is linked to age-related diseases. The presence of interfaces can affect their aggregation mechanism, often speeding up aggregation. -Synuclein (Syn) can adsorb to biomolecular condensates, leading to heterogenous nucleation and faster aggregation. Understanding the mechanism underlying localization of amyloidogenic proteins at condensate interfaces is crucial for developing strategies to prevent or reverse their binding. We show that Syn localization to the surface of peptide-based heterotypic condensates is an adsorption process governed by the proteins condensate-amphiphilic nature. Adsorption occurs in multiple layers and levels off at micromolar concentrations. Based on these findings, we design three strategies to modulate Syn accumulation: (i) addition of biomolecules that decrease the condensate {zeta}-potential, such as NTPs and RNA, (ii) competitive adsorption of proteins targeting the condensate interface, such as G3BP1, DDX4-YFP, EGFP-NPM1, Hsp70, Hsc70, and (iii) preferential adsorption of Syn to membranes. Removing Syn from the condensate interface slows aggregation, highlighting potential cellular control over protein adsorption and implications for therapeutic strategies. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=128 SRC="FIGDIR/small/619145v1_ufig1.gif" ALT="Figure 1"> View larger version (39K): org.highwire.dtl.DTLVardef@159b012org.highwire.dtl.DTLVardef@1369671org.highwire.dtl.DTLVardef@ced970org.highwire.dtl.DTLVardef@2578b0_HPS_FORMAT_FIGEXP M_FIG C_FIG

biophysics↗

bioRxiv2017

Postmating sexual selection and the enigmatic jawed genitalia of Callosobruchus subinnotatus

Insect genitalia exhibit rapid divergent evolution. Truly extraordinary structures have evolved in some groups, presumably as a result of post-mating sexual selection. To increase our understanding of this phenomenon, we studied the function of one such structure. The male genitalia of Callosobruchus subinnotatus (Coleoptera: Bruchinae) contain a pair of jaw-like structures with unknown function. Here, we used phenotypic engineering to ablate the teeth on these jaws. We then experimentally assessed the effects of ablation of the genital jaws on mating duration, ejaculate weight, male fertilization success and female fecundity, using a double-mating experimental design. We predicted that copulatory wounding in females should be positively related to male fertilization success. However, we found no significant correlation between genital tract scarring in females and male fertilization success. Male fertilization success was, however, positively related to the amount of ejaculate transferred by males and negatively related to female ejaculate dumping. Ablation of male genital jaws did not affect male relative fertilization success but resulted in a reduction in female egg production. Our results suggest that postmating sexual selection in males indeed favors these genital jaws, but not primarily through an elevated relative success in sperm competition but by increasing female egg production.

evolutionary biology↗