An atypical soybean leucine-rich repeat receptor-like kinase, GmLRK1, may be involved in the regulation of cell elongation.

A leucine-rich repeat receptor-like kinase (LRR-RLK) encoded by one of the genes highly expressed in a specific stage of soybean seed development, referred to as GmLRK1, was identified and characterized. Examination of its kinase domain indicated that GmLRK1 may be a catalytically inactive atypical receptor kinase. An autophosphorylation assay confirmed that GmLRK1 is incapable of autophosphorylation in vitro. However, the phosphorylation of GmRLK1 could be induced after incubation with plant protein extracts, suggesting that some plant proteins may interact with GmLRK1 and phosphorylate the protein in vivo. Analyses of the expression profiles of GmLRK1 and its Arabidopsis ortholog At2g36570 revealed that they may be involved in regulation of more fundamental metabolic and/or developmental pathways, rather than a specialized developmental program such as seed development. Our results further indicate that the GmLRK1 and At2g36570 may play a role in the regulation of certain cellular processes that lead to cell elongation and expansion.