WUSCHEL-Responsive At5g65480 Interacts with CLAVATA Components In Vitro and in Transient Expression

Abstract

<div><p>The CLAVATA (CLV) signaling pathway is essential for shoot meristem homeostasis in Arabidopsis. CLV acts to limit the expression domain of the stem cell-promoting gene <i>WUSCHEL</i> (<i>WUS</i>). The closely related receptor-kinases CLV1 and BAM1 are key components in this pathway; however, the downstream factors that link the receptors to <i>WUS</i> regulation are poorly understood. The Arabidopsis gene <i>At5g65480</i> was recently identified as a direct transcriptional target up-regulated by WUS. We have independently identified this gene which we term CCI1 as a CLV1 and BAM1 interacting protein in vitro and in transient expression. CCI1 has phosphatidylinositide-binding activity in vitro and localizes to the plasma membrane in transient expression. Furthermore, CLV signaling components and CCI1 both partition to detergent-resistant membrane microdomains characterized as lipid rafts.</p></div