ARR10

ARR10, short for Arabidopsis Response Regulator 10, is a protein encoded by a gene in Arabidopsis thaliana. It is a member of the type-B Arabidopsis Response Regulator (ARR) family and functions as part of the plant’s cytokinin signaling pathway, which uses a two-component signaling system to regulate gene expression in response to cytokinin.

In cytokinin signaling, receptors perceive cytokinin and initiate a phosphorelay through histidine phosphotransfer proteins to nuclear response regulators. ARR10 acts as a transcription factor that modulates the expression of cytokinin-responsive genes, often working in concert with other type-B ARRs to shape the transcriptional response.

ARR10 shares the characteristic architecture of type-B ARRs, containing an N-terminal receiver domain and a C-terminal output region that supports transcriptional activation. It localizes to the nucleus, where it binds DNA and influences the transcription of target genes involved in growth and development.

Biological roles attributed to ARR10 include participation in cytokinin-regulated processes such as shoot and root development, meristem activity, and leaf formation. Genetic interactions with other type-B ARRs, notably ARR1 and ARR12, have been observed, indicating that ARR10 contributes to a broader regulatory network and participates in feedback mechanisms with type-A ARRs to modulate cytokinin signaling strength.

ARR10 activity is controlled by phosphorylation through histidine kinases and phosphotransfer proteins, with its transcriptional output further modulated by cytokinin levels and other regulatory inputs. The protein serves as a widely used model for studying cytokinin signaling and its integration with plant development and hormonal cross-talk, including interactions with auxin signaling in some contexts.