No abstract

The centrosome, a non-membranous organelle, constrains various soluble molecules locally to execute its functions. As the centrosome is surrounded by various dense components, we hypothesized that it may be bordered by a putative diffusion barrier. After quantitatively measuring the trapping kinetics of soluble proteins of varying size at centrosomes by a chemically inducible diffusion trapping assay, we find that centrosomes are highly accessible to soluble molecules with a Stokes radius of less than 5.8 nm, whereas larger molecules rarely reach centrosomes, indicating the existence of a size-dependent diffusion barrier at centrosomes. The permeability of this barrier is tightly regulated by branched actin filaments outside of centrosomes and it decreases during anaphase when branched actin temporally increases. The actinbased diffusion barrier gates microtubule nucleation by interfering with c-tubulin ring complex recruitment. We propose that actin filaments spatiotemporally constrain protein complexes at centrosomes in a size-dependent manner.

Organic small molecular materials with coplanar π‐conjugated system as HTMs in perovskite solar cells (PSCs) have attracted considerable attention due to their high charge transport capability and thermal stability. Herein, three novel pentafulvalene‐fused derivatives with or without fluorine atoms incorporated (YSH‐oF and YSH‐mF and YSH‐H, respectively) are designed, synthesized, and applied as hole‐transporting materials (HTMs) in PSCs fabrication. The fluorinated HTMs, YSH‐oF and YSH‐mF, exhibited higher hole mobility and better charge extraction at the perovskite/HTM interface than non‐fluorinated one do, presumably due to the closer intermolecular π–π packing interactions. As a result, small‐area (0.09 cm2) PSCs made with YSH‐oF and YSH‐mF achieved an impressive power conversion efficiency (PCE) of 23.59% and 22.76% respectively, with negligible hysteresis, in contrast with the 20.57% for the YSH‐H‐based devices. Furthermore, for large‐area (1.00 cm2) devices, the PSCs employing YSH‐oF exhibited a PCE of 21.92%. Moreover, excellent long‐term device stability is demonstrated for PSCs with F‐substituted HTMs (YSH‐oF and YSH‐mF), presumably due to the higher hydrophobicity. This study shows the great potential of fluorinated pentafulvalene‐fused materials as low‐cost HTM for efficient and stable PSCs.

24Biomolecules that respond to different external stimuli enable the remote control of genetically 25 modified cells. Chemogenetics and optogenetics, two tools that can control cellular activities 26 via synthetic chemicals or photons, respectively, have been widely used to elucidate underlying 27 physiological processes. These methods are, however, very invasive, have poor penetrability, 28 or low spatiotemporal precision, attributes that hinder their use in therapeutic applications. We 29 report herein a sonogenetic approach that can manipulate target cell activities by focused 30 ultrasound stimulation. This system requires an ultrasound-responsive protein derived from an 31 engineered auditory-sensing protein prestin. Heterogeneous expression of mouse prestin 32 containing two parallel amino acid substitutions, N7T and N308S, that frequently exist in 33 prestins from echolocating species endowed transfected mammalian cells with the ability to 34 sense ultrasound. An ultrasound pulse of low frequency and low pressure efficiently evoked 35 cellular calcium responses after transfecting with prestin(N7T, N308S). Moreover, pulsed 36 ultrasound can also non-invasively stimulate target neurons expressing prestin(N7T, N308S) 37 in deep regions of mice brains. Our study delineates how an engineered auditory-sensing 38 protein can cause mammalian cells to sense ultrasound stimulation. Moreover, owing to the 39 great penetration of low-frequency ultrasound (~400 mm in depth), our sonogenetic tools will 40 serve as new strategies for non-invasive therapy in deep tissues of large animals like primates. 41 42 43 44 45 46