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Cellular proteins are dynamically regulated in response to environmental stimuli. Conventional proteomics compares the entire proteome in different cellular states to identify differentially expressed proteins, which suffers from limited sensitivity for analyzing acute and subtle changes. To address this challenge, nascent proteomics has been developed, which selectively analyzes the newly synthesized proteins, thus offering a more sensitive and timely insight into the dynamic changes of the proteome. In this Minireview, we discuss recent advancements in nascent proteomics, with an emphasis on methodological developments. Also, we delve into the current challenges and provide an outlook on the future prospects of this exciting field. [ABSTRACT FROM AUTHOR]

Chiral nanographenes with both high fluorescence quantum yields (ΦF) and large dissymmetry factors (glum) are essential to the development of circularly polarized luminescence (CPL) materials. However, most studies have been focused on the improvement of glum, whereas how to design highly emissive chiral nanographenes is still unclear. In this work, we propose a new design strategy to achieve chiral nanographenes with high ΦF by helical π‐extension of strongly luminescent chromophores while maintaining the frontier molecular orbital (FMO) distribution pattern. Chiral nanographene with perylene as the core and two dibenzo[6]helicene fragments as the wings has been synthesized, which exhibits a record high ΦF of 93 % among the reported chiral nanographenes and excellent CPL brightness (BCPL) of 32 M−1 cm−1. [ABSTRACT FROM AUTHOR]

Metabolic labeling with clickable noncanonical amino acids has enabled nascent proteome profiling, which can be performed in a cell‐type‐specific manner. However, nascent proteomics in an intercellular communication‐dependent manner remains challenging. Here we develop communication‐activated profiling of protein expression (CAPPEX), which integrates the LuxI/LuxR quorum sensing circuit with the cell‐type‐specific nascent proteomics method to enable selective click‐labeling of newly synthesized proteins in a specific bacterium upon receiving chemical signals from another reporter bacterium. CAPPEX reveals that E. coli competes with Salmonella for tryptophan as the precursor for indole, and the resulting indole suppressed the expression of virulence factors in Salmonella. This tryptophan‐indole axis confers attenuation of Salmonella invasion in host cells and living mice. The CAPPEX strategy should be widely applicable for investigating various interbacterial communication processes. [ABSTRACT FROM AUTHOR]

Single‐cell RNA sequencing (scRNA‐seq) has emerged as a powerful tool for profiling gene expression of distinct cell populations at the single‐cell level. However, the information of the positions of cells within the multicellular samples is missing in scRNA‐seq datasets. To overcome this limitation, we herein develop OpTAG (optical cell tagging) as a new chemical platform for attaching functional tags onto cell surfaces in a spatially resolved manner. With OpTAG, we establish OpTAG‐seq, which enables spatially resolved scRNA‐seq. We apply OpTAG‐seq to investigate the spatially defined transcriptional program in migrating cancer cells and identified a list of genes that are potential regulators for cancer cell migration and invasion. OpTAG‐seq provides a convenient method for mapping cellular heterogeneity with spatial information within multicellular biological systems. [ABSTRACT FROM AUTHOR]

Protein lipoylation is a post‐translational modification of emerging importance in both prokaryotes and eukaryotes. However, labeling and large‐scale profiling of protein lipoylation remain challenging. Here, we report the development of iLCL (iodoacetamide‐assisted lipoate‐cyclooctyne ligation), a chemoselective reaction that enables chemical tagging of protein lipoylation. We demonstrate that the cyclic disulfide of lipoamide but not linear disulfides can selectively react with iodoacetamide to produce sulfenic acid, which can be conjugated with cyclooctyne probes. iLCL enables tagging of lipoylated proteins for gel‐based detection and cellular imaging. Furthermore, we apply iLCL for proteomic profiling of lipoylated proteins in both bacteria and mammalian cells. In addition to all of the eight known lipoylated proteins, we identified seven candidates for novel lipoylated proteins. The iLCL strategy should facilitate uncovering the biological function of protein lipoylation. [ABSTRACT FROM AUTHOR]

CD22, a member of Siglec family of sialic acid binding proteins, has restricted expression on B cells. Antibody‐based agents targeting CD22 or CD20 on B lymphoma and leukemia cells exhibit clinical efficacy for treating these malignancies, but also attack normal B cells leading to immune deficiency. Here, we report a chemoenzymatic glycocalyx editing strategy to introduce high‐affinity and specific CD22 ligands onto NK‐92MI and cytokine‐induced natural killer cells to achieve tumor‐specific CD22 targeting. These CD22‐ligand modified cells exhibited significantly enhanced tumor cell binding and killing in vitro without harming healthy B cells. For effective lymphoma cell killing in vivo, we further functionalized CD22 ligand‐modified NK‐92MI cells with the E‐selectin ligand sialyl Lewis X to promote trafficking to bone marrow. The dual‐functionalized cells resulted in the efficient suppression of B lymphoma in a xenograft model. Our results suggest that natural killer cells modified with glycan ligands to CD22 and selectins promote both targeted killing of B lymphoma cells and improved trafficking to sites where the cancer cells reside, respectively. [ABSTRACT FROM AUTHOR]