Receptor-like proteins: searching for functions.

Receptor-like proteins (RLPs) are cell surface receptors, which are composed of several distinct domains including a signal peptide, an extracellular leucine-rich repeat (LRR) region, a transmembrane domain and a short cytoplasmic tail. RLPs are implicated in plant growth and development as well as in disease resistance. Our previous genome-wide functional analysis of 57 Arabidopsis RLP genes (AtRLPs) revealed that mutant phenotypes were only observed for a few genes including the two reported genes CLAVATA2 (CLV2) and TOO MANY MOUTHS, despite the wide range of growth and developmental stages and treatments that were tested. In a recent study, we reported on further insights into the biological role of a few AtRLPs closely-related to CLV2. Two AtRLPs (AtRLP2 and AtRLP12), which share high sequence similarity with CLV2, were found to be able to rescue the clv2 mutant phenotype when expressed under the control of the CLV2 promoter, suggesting that the specialization among CLV2, AtRLP2 and AtRLP12 is largely ascribed to differences in their expression patterns. Our data further indicated that the island domain of CLV2 is dispensable for its function and the C3-F domain of CLV2 could be replaced by that of AtRLP38. In this Addendum, we are elaborating on further strategies concerning the function of largely unknown AtRLPs.