Link-Lenczowski, P. | Search bioRxiv

bioRxiv2025

Type 1 LacNAc and LacdiNAc on N-glycans as molecular biomarkers of human melanoma cells

Melanoma, the most dangerous form of skin cancer, is characterized by its high potential to spread or metastasize. Tumor progression is associated with changes in glycosylation that occur early in carcinogenesis and evolve as the cancer develops and spreads. To identify new melanoma transformation markers, we analyzed N-glycans from melanocytes and melanoma cell lines at different progression stages. We performed analyses using matrix-assisted laser desorption/ionization (MALDI)-mass spectrometry (MS) and hydrophilic interaction liquid chromatography (HILIC)-high performance liquid chromatography (HPLC) techniques on N-glycans without and after digestion with exoglycosidase arrays. Our results showed that, unlike melanocytes, melanoma cells express higher levels of type 1 LacNAc units and triantennary complex type glycans instead of high-mannose type glycans. Our results revealed that the N-glycomes of all analyzed cell lines possess Lewis X/A epitopes and, for the first time, demonstrate the presence of Gal{beta}1-4Gal{beta}1-4GlcNAc and Gal{beta}1-3Gal{beta}1-3GlcNAc units. The characteristic feature of melanoma cells is the presence of LacdiNAc structures. Our study provides the first comprehensive characterization of the N-glycome of melanocytes and suggests novel glyco-biomarkers of melanoma progression.

cancer biology↗

bioRxiv2021

HSFA1 proteins mediate heat-induced accumulation of CPT7-derived polyprenols affecting thylakoid organization

Polyprenols are ubiquitous isoprenoid compounds that accumulate in large quantities in plant photosynthetic tissues. While our knowledge of polyprenol biochemistry is constantly expanding, the regulation of their biosynthesis as well as the molecular basis of their cellular action are still poorly understood. In Arabidopsis, the polyprenols Pren-9, -10 and -11, synthesized by cis-prenyltransferase 7 (CPT7), are localized in plastidial membranes and affect the photosynthetic performance of chloroplasts. In this report we present evidence that plastidial polyprenols are among the major constituents of thylakoid membranes. Disturbances in polyprenol level, caused by alterations in CPT7 expression, change chloroplast ultrastructure, affect aggregation of LHCII complexes and modulate non-photochemical quenching (NPQ). Moreover, we show that Arabidopsis responds to high temperature by upregulating expression of CPT7 and increasing the accumulation of CPT7-derived polyprenols. These heat-induced changes in polyprenol biosynthesis are mediated by Heat Shock Transcription Factors of the HSFA1 family, the master regulators of heat stress response. Collectively, results presented in this report bring us closer to understanding the mechanisms by which polyprenols affect plant physiology and provide an additional link between chloroplast biology and plant responses to changing environmental conditions. One sentence summaryHeat Shock Transcription Factors induce biosynthesis of polyprenols - isoprenoid compounds that affect the organization and function of chloroplasts.

plant biology↗