SATB1 undergoes isoform-specific phase transitions in T cells

Intracellular space is demarcated into functional membraneless organelles and nuclear bodies via the process of phase separation. Phase transitions are involved in many functions linked to such bodies as well as in gene expression regulation and other cellular processes. In this work we describe how the genome organizer SATB1 utilizes its prion-like domains to undergo phase transitions. We have identified two SATB1 isoforms with distinct biophysical behavior and showed how phosphorylation and interaction with nuclear RNA, impact their phase transitions. Moreover, we show that SATB1 is associated with transcription and splicing, both of which evinced deregulation in Satb1 knockout mice. Thus, the tight regulation of different SATB1 isoforms levels and their post-translational modifications are imperative for SATB1's physiological roles in T cell development while their deregulation may be linked to disorders such as cancer.

Refining the Design of Diblock Elastin-Like Polypeptides for Self-Assembly into Nanoparticles

Diblock copolymers based-on elastin-like polypeptide (ELP) have the potential to undergo specific phase transitions when thermally stimulated. This ability is especially suitable to form carriers, micellar structures for instance, for delivering active cargo molecules. Here, we report the design and study of an ELP diblock library based on ELP-[M1V3-i]-[I-j]. First, ELP-[M1V3-i]-[I-j] (i = 20, 40, 60; j = 20, 90) that showed a similar self-assembly propensity (unimer-to-aggregate transition) as their related monoblocks ELP-[M1V3-i] and ELP-[I-j]. By selectively oxidizing methionines of ELP-[M1V3-i] within the different diblocks structures, we have been able to access a thermal phase transition with three distinct regimes (unimers, micelles, aggregates) characteristic of well-defined ELP diblocks.

On Specific Phase Transitions to the Compound-Like Impurity Nanosegregation Structures at Dislocations and Grain Boundaries in Metals and their Influence on Diffusion-Assisted Processes

Specific phase transitions to the compound-like impurity nanosegregation structures at dislocations and grain boundaries in metals and their influence on diffusion-assisted processes are considered, mainly, on the basis of the thermodynamic analysis of the related experimental data. The following systems and aspects are in detail considered: (1) the hydride-like nanosegregation of hydrogen at dislocations and grain boundaries in palladium and their influence on the apparent characteristics of hydrogen solubility and diffusivity in palladium; (2) the physics of the anomalous characteristics of diffusion of Fe and other transition impurities in crystalline Al at elevated temperatures, the role of the compound-like nanosegregation (CLNS) of Fe and the others at dislocations and grain boundaries in Al, analysis of the Mössbauer and diffusion data on CLNS of Fe at grain boundaries and dislocations in Al; (3) some new physical aspects of internal oxidation and nitridation of metals (for Cu-0.3%Fe alloy/Cu2O surface layer, and for (Ni-5%Cr) alloy / N2 gas), the role of the compound-like impurity nanosegregation at dislocations and grain boundaries, study results on the deviations from the classical theories predictions and their interpretation. The possibility is considered of nanotechnology applications of the study results for creation of nanostructured metals with compound-like nanosegregation structures at grain boundaries, in order to obtain specific physical and mechanical properties of such a cellural-type nanocomposites. In particular, it can be complex hydride-like, carbide-like, nitride-like, carbide-nitride-like, oxide-like or intermetallide-like nanosegregation structures at grain boundaries of nanostructured metals.