NKS1/ELMO4 is an integral protein of a pectin synthesis protein complex and maintains Golgi morphology and cell adhesion in Arabidopsis

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 121; no. 15; p. e2321759121
• Main Authors: Lathe, Rahul S, McFarlane, Heather E, Kesten, Christopher, Wang, Liu, Khan, Ghazanfar Abbas, Ebert, Berit, Ramírez-Rodríguez, Eduardo Antonio, Zheng, Shuai, Noord, Niels, Frandsen, Kristian, Bhalerao, Rishikesh P, Persson, Staffan
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 09.04.2024
• Subjects: Abscission; Adhesion; Arabidopsis; Arabidopsis - metabolism; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Biosynthesis; Cell adhesion; Cell adhesion & migration; Cell Adhesion - genetics; Cell Biology; Cell Wall - metabolism; Cell walls; Cellbiologi; Cytology; Golgi Apparatus - genetics; Golgi Apparatus - metabolism; Golgi cells; Integrity; Lamellae; Mutants; Pectin; Pectins - metabolism; Phenotypes; Plant cells; Polysaccharides; Protein biosynthesis; Proteins; Ripening; Saccharides; Seedlings; Structure-function relationships; cell biology; Arabidopsis; cell walls; pectin; Golgi apparatus
• ISSN: 0027-8424; 1091-6490; 1091-6490
• DOI: 10.1073/pnas.2321759121

Adjacent plant cells are connected by specialized cell wall regions, called middle lamellae, which influence critical agricultural characteristics, including fruit ripening and organ abscission. Middle lamellae are enriched in pectin polysaccharides, specifically homogalacturonan (HG). Here, we identify a plant-specific DUF1068 protein, called NKS1/ELMO4, that is required for middle lamellae integrity and cell adhesion. NKS1 localizes to the Golgi apparatus and loss of NKS1 results in changes to Golgi structure and function. The mutants also display HG deficient phenotypes, including reduced seedling growth, changes to cell wall composition, and tissue integrity defects. These phenotypes are comparable to and mutants, which are defective in HG biosynthesis. Notably, genetic interactions indicate that NKS1 and the QUAs work in a common pathway. Protein interaction analyses and modeling corroborate that they work together in a stable protein complex with other pectin-related proteins. We propose that NKS1 is an integral part of a large pectin synthesis protein complex and that proper function of this complex is important to support Golgi structure and function.