Biology subjects

Wang, W. C.

Publications and source records attributed to Wang, W. C..

4 recordsLinked to original sources

bioRxiv2024

Inhibition of GEF-H1-RhoA signaling in inflammation with a stapled peptide mimicry of the RhoA67-78 helix

Guanine exchange factors (GEFs) are considered hard to drug with conventional small molecules, they lack conventional deep binding pockets and binding ligands are seldom reported. Here we report the design of a stapled peptide stP5 targeting the interaction between cytoskeletal regulator RhoA GTPase and its activator guanine exchange factor H1 (GEF-H1). StP5 is a modified RhoA mimic based on a previously identified bioactive -helical epitope to GEF-H1. StP5 effectively inhibits GEF-H1-induced morphological and transcriptional changes in cellular models for inflammation and does not affect the related GEF p114RhoGEF (ARHGEF18). StP5 peptide is approximately 100 fold more active in cellular assays than the unstapled P5 peptide. We provide a bioinformatic analysis of the stP5 bindings site in different GEFs, providing a basis for this selectivity. The GEF-H1 inhibitor stP5 represents a step towards fully drugging GEF-H1. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=102 SRC="FIGDIR/small/624118v1_ufig1.gif" ALT="Figure 1"> View larger version (38K): org.highwire.dtl.DTLVardef@d783b3org.highwire.dtl.DTLVardef@10798b2org.highwire.dtl.DTLVardef@1ba0817org.highwire.dtl.DTLVardef@693367_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗

bioRxiv2021

The E26 Transformation-Specific-family transcription factor Spi-C is dynamically regulated by external signals in B cells

Spi-C is an E26 transformation-specific transcription factor closely related to PU.1 and Spi-B. Spi-C has lineage-instructive functions important in antibody-generating responses, B cell development, and red pulp macrophage generation. Spi-C is inducible by heme- and NF-{kappa}B-dependent pathways in macrophages. The present research aimed to examine the regulation of Spi-C expression in B cells. RT-qPCR analysis revealed that Spic expression was reduced in B cells following addition of lipopolysaccharide, anti-IgM antibodies, CD40L, or cytokines BAFF + IL-4 + IL-5. Cytochalasin treatment partially prevented downregulation of Spic. Unstimulated B cells upregulated Spic over time in culture. To determine the mechanism of Spic regulation, we examined the Spic promoter and upstream regulatory elements. The Spic promoter had unidirectional activity, which was reduced by mutation of an NF-{kappa}B binding site. Spic was repressed by an upstream regulatory region interacting with the heme-binding regulator Bach2. Taken together, these data indicate that Spi-C is dynamically regulated by external signals in B cells and provide insight into the mechanism of regulation.

immunology↗

bioRxiv2021

BCOR and BCORL1 mutations disrupt PRC1.1 repressive function in leukemia by unlinking the RING-PCGF1 enzymatic core from target genes

BCOR and its paralog BCORL1 encode subunits of the Polycomb repressive complex 1.1 (PRC1.1) and are recurrently mutated in myeloid malignancies. We show that leukemia-associated BCOR/BCORL1 mutations unlink the PRC1.1 RING-PCGF enzymatic core from the KDM2B-containing chromatin targeting auxiliary subcomplex, either by causing complete protein loss or expression of a C-terminally truncated protein lacking the PCGF Ub-like fold discriminator (PUFD) domain. By uncoupling PRC1.1 repressive function from target genes, BCOR/BCORL1 mutations activate aberrant cell signaling programs that confer acquired resistance to treatment. This study provides a mechanistic basis for Polycomb repressive dysfunction as a key oncogenic driver in myeloid malignancies and identifies a potential strategy for targeted therapy in BCOR-mutated cancer.

cancer biology↗

bioRxiv2021

L-WNK1 is required for BK channel activation in intercalated cells

BK channels expressed in intercalated cells (ICs) in the aldosterone-sensitive distal nephron (ASDN) mediate flow-induced K+ secretion. In the ASDN of mice and rabbits, IC BK channel expression and activity increase with a high K+ diet. In cell culture, the long isoform of the kinase WNK1 (L-WNK1) increases BK channel expression and activity. Apical L-WNK1 expression is selectively enhanced in ICs in the ASDN of rabbits on a high K+ diet, suggesting that L-WNK1 contributes to BK channel regulation by dietary K+. We examined the role of IC L-WNK1 expression in enhancing BK channel activity in response to a high K+ diet. Mice with an IC-selective deletion of L-WNK1 (IC-L-WNK1-KO) and littermate control mice were placed on a high K+ (5% K+ as KCl) diet for at least 10 days. IC-L-WNK1-KO mice exhibited higher blood K+ concentrations ([K+]) than controls. BK channel-dependent whole-cell currents in ICs from cortical collecting ducts of high K+ fed IC-L-WNK1-KO mice were reduced compared to controls. Six-hour urinary K+ excretion in response a saline load was similar in IC-L-WNK1-KO mice and controls. The observations that IC-L-WNK1-KO mice have higher blood [K+] and reduced IC BK channel currents are consistent with impaired urinary K+ secretion, and suggest that IC L-WNK1 has a role in the renal adaptation to a high K+ diet.

physiology↗