No abstract

Hydrogen sulfide (H2S) is an endogenously generated and putative signaling/effector molecule. In spite of its numerous reported functions, the chemistry by which it elicits its functions is not understood. Moreover, recent studies allude to the existence of other sulfur species besides H2S that may play critical physiological roles. Herein, the basic chemical biology of H2S as well as other related or derived species is discussed and reviewed. A particular focus of this review are the per- and poly-sulfides which are likely in equilibrium with free H2S and which may be important biological effectors themselves.

Inhibition of IL-17 receptor A did not produce a treatment effect in subjects with asthma. The results of the high-reversibility subgroup analysis are of uncertain significance, requiring further study of brodalumab in this asthma subpopulation. Clinical trial registered with www.clinicaltrials.gov (NCT01199289).

The receptor-type protein tyrosine phosphatase (RPTP) CD148 is thought to have an inhibitory function in signaling and proliferation in nonhematopoietic cells. However, its role in the immune system has not been thoroughly studied. Our analysis of CD148 loss-of-function mice showed that CD148 has a positive regulatory function in B cells and macrophages, similar to the role of CD45 as a positive regulator of Src family kinases (SFKs). Analysis of CD148 and CD45 doubly deficient B cells and macrophages revealed hyperphosphorylation of the C-terminal inhibitory tyrosine of SFKs accompanied by substantial alterations in B and myeloid lineage development and defective immunoreceptor signaling. Because these findings suggest the C-terminal tyrosine of SFKs is a common substrate for both CD148 and CD45 phosphatases and imply a level of redundancy not previously appreciated, a reassessment of the function of CD45 in the B and myeloid lineages based on prior data from the CD45-deficient mouse is warranted.

The linker for activation of T cells (LAT) is essential for signaling through the T cell receptor (TCR).

The chemical biology of thiols (RSH, e.g., cysteine and cysteine‐containing proteins/peptides) has been a topic of extreme interest for many decades due to their reported roles in protein structure/folding, redox signaling, metal ligation, cellular protection, and enzymology. While many of the studies on thiol/sulfur biochemistry have focused on thiols, relatively ignored have been hydropersulfides (RSSH) and higher order polysulfur species (RSSnH, RSSnR, n > 1). Recent and provocative work has alluded to the prevalence and likely physiological importance of RSSH and related RSSnH. RSSH of cysteine (Cys‐SSH) has been found to be prevalent in mammalian systems along with Cys‐SSH‐containing proteins. The RSSH functionality has not been examined to the extent of other biologically relevant sulfur derivatives (e.g., sulfenic acids, disulfides, etc.), whose roles in cell signaling are strongly indicated. The recent finding of Cys‐SSH biosynthesis and translational incorporation into proteins is an unequivocal indication of its fundamental importance and necessitates a more profound look into the physiology of RSSH. In this Review, we discuss the currently reported chemical biology of RSSH (and related species) as a prelude to discussing their possible physiological roles.

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LAT, a transmembrane adapter protein found in glycolipid-enriched microdomains (GEMs), is essential for T cell activation. In this study, we have utilized a LATdeficient mutant of the Jurkat T cell line, J.CaM2, to explore various requirements for LAT function. First, we demonstrate that LAT must be present in GEMs for coupling T cell receptor (TCR) engagement to activation of the Ras signaling pathway, increases in intracellular Ca 2؉ , and induction of the transcription factor nuclear factor of activated T cells (NF-AT). Second, we show that the extracellular and transmembrane domains of LAT are dispensable for these TCR-mediated events once LAT has localized to GEMs. These results provide important insights into both the structural domains of LAT and its subcellular localization that are required for effective TCR signaling.