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An Arabidopsis cell wall-associated kinase required for invertase activity and cell growth

Kohorn, Bruce D., Kobayashi, Masaru, Johansen, Sue, Riese, Jeff, Huang, Li-Fen, Koch, Karen, Fu, Sarita, Dotson, Anjali, Byers, Nicole
The plant journal 2006 v.46 no.2 pp. 307-316
Arabidopsis, beta-fructofuranosidase, cell growth, cell walls, kinases, metabolism, mutation, pectins, plasma membrane, proteins, salts, seedling growth, serine, sugars
The wall-associated kinases (WAK), a family of five proteins that contain extracellular domains that can be linked to pectin molecules of the cell wall, span the plasma membrane and have a cytoplasmic serine/threonine kinase domain. Previous work has shown that a reduction in WAK protein levels leads to a loss of cell expansion, indicating that these receptor-like proteins have a role in cell shape formation. Here it is shown that a single wak2 mutation exhibits a dependence on sugars and salts for seedling growth. This mutation also reduces the expression and activity of vacuolar invertase, often a key factor in turgor and expansion. WAKs may thus provide a molecular mechanism linking cell wall sensing (via pectin attachment) to regulation of solute metabolism, which in turn is known to be involved in turgor maintenance in growing cells.