||This article needs attention from an expert on the subject. (March 2010)|
Arabinogalactan protein (AGPs)
Arabinogalactan protein is a broad term applied to diverse class of cell surface glycoproteins present in plant cell walls. It is heavily glycosylated, with only 2-10% comprising the protein region.The protein family has been earlier reported to contain O-linked glycans, whereas recent efforts employing mass spectrometry have revealed the presence of N-linked glycans as well within this protein family isolated from elongating cotton fiber cells.
Structure of Arabinogalactan Protein (AGPs)
AGPs contains protein backbone of varied length (5-30kDa) with N-terminal secretory peptide followed by AGP, Fasciclin domains and a C-terminal glycosylphosphatidylinositol (GPI) lipid anchor site. In some plant cells, the length of the mature protein backbone is only 10-13 residues long and they are therefore called as Arabinogalactan peptides. The protein backbone contains domain rich in hydroxyproline/proline, serine, alanine and glycine amino acids. The repeated occurrence of Alanine/Serine/Threonine-Proline stretch (glycomodules) and the presence of hydroxyproline suggests the sites for O-linked glycosylation and arabinogalactan modification. The O-linked glycan chains predominantly contain galactose, arabinose, rhamnose, mannose, galacturonic acid and/or glucuronic acids and have a relatively high degree of polymerization, with a structure similar to arabinogalactan II.
Biological roles of AGPs
AGPs are known to be involved in many biological processes like cell division, cell elongation, cell death, pattern formation, maintenance of post embryonic pattern, vascular, gametophyte development, signalling, root-microbe interaction etc.
- Seifert, Georg J.; Roberts, Keith (January 2, 2007). "The Biology of Arabinogalactan Proteins". Annual Review of Plant Biology 58 (1): 137–61. doi:10.1146/annurev.arplant.58.032806.103801.
- Kumar, Saravanan; Kumar, K; Pandey, P; Rajamani, V; Padmalatha, KV; Dhandapani, G; Kanakachari, M; Leelavathi, S; Kumar, PA; Reddy, VS (December 1, 2013). "Glycoproteome of elongating cotton fiber cells.". Molecular & cellular proteomics : MCP 12 (12): 3677–89. doi:10.1074/mcp.M113.030726. PMID 24019148.
- Schultz, CJ; Johnson, KL; Currie, G; Bacic, A (September 2000). "The classical arabinogalactan protein gene family of arabidopsis.". The Plant cell 12 (9): 1751–68. doi:10.1105/tpc.12.9.1751. PMID 11006345.
- McNeil M, Darvill AG, Fry SC, Albersheim P. (1984) Structure and function of primary cell walls of plants. Anna Rev Biochem 53:625-663
- Serpe, Marcelo D.; Nothnagel, Eugene A. "Effects of Yariv phenylglycosides onRosa cell suspensions: Evidence for the involvement of arabinogalactan-proteins in cell proliferation". Planta 193 (4): 542–550. doi:10.1007/BF02411560.
- van Hengel, AJ; Roberts, K (October 2002). "Fucosylated arabinogalactan-proteins are required for full root cell elongation in arabidopsis.". The Plant journal : for cell and molecular biology 32 (1): 105–13. doi:10.1046/j.1365-313x.2002.01406.x. PMID 12366804.
- Gao, Minggeng; Showalter, Allan M. "Yariv reagent treatment induces programmed cell death in Arabidopsis cell cultures and implicates arabinogalactan protein involvement". The Plant Journal 19 (3): 321–331. doi:10.1046/j.1365-313X.1999.00544.x.
- Knox, JP; Linstead, PJ; Peart, J; Cooper, C; Roberts, K (November 1991). "Developmentally regulated epitopes of cell surface arabinogalactan proteins and their relation to root tissue pattern formation.". The Plant journal : for cell and molecular biology 1 (3): 317–26. doi:10.1046/j.1365-313X.1991.t01-9-00999.x. PMID 21736649.
- Nguema-Ona, Eric; Vicré-Gibouin, Maïté; Cannesan, Marc-Antoine; Driouich, Azeddine. "Arabinogalactan proteins in root–microbe interactions". Trends in Plant Science 18 (8): 440–449. doi:10.1016/j.tplants.2013.03.006.