Developmental cues are encoded by the combinatorial phosphorylation of Arabidopsis RETINOBLASTOMA-RELATED protein RBR1.

RETINOBLASTOMA-RELATED (RBR) proteins orchestrate cell division, differentiation, and survival in response to environmental and developmental cues through protein-protein interactions that are governed by multisite phosphorylation. Here we explore, using a large collection of transgenic RBR phosphovariants to complement protein function in Arabidopsis thaliana, whether differences in the number and position of RBR phosphorylation events cause a diversification of the protein's function. While the number of point mutations influence phenotypic strength, phosphosites contribute differentially to distinct phenotypes.

The dual role of the RETINOBLASTOMA-RELATED protein in the DNA damage response is coordinated by the interaction with LXCXE-containing proteins.

Living organisms possess mechanisms to safeguard genome integrity. To avoid spreading mutations, DNA lesions are detected and cell division is temporarily arrested to allow repair mechanisms. Afterward, cells either resume division or respond to unsuccessful repair by undergoing programmed cell death (PCD).

Tuning Division and Differentiation in Stomata: How to Silence a MUTE.

Precise coordination of cell differentiation and division within a tissue context is critical for plant development. In this issue of Developmental Cell, Han et al. (2018) report a transcriptional switch that ensures proper patterning, the final cell division, and terminal differentiation of stomata.

Two maize Kip-related proteins differentially interact with, inhibit and are phosphorylated by cyclin D-cyclin-dependent kinase complexes.

The family of maize Kip-related proteins (KRPs) has been studied and a nomenclature based on the relationship to rice KRP genes is proposed. Expression studies of KRP genes indicate that all are expressed at 24 h of seed germination but expression is differential in the different tissues of maize plantlets. Recombinant KRP1;1 and KRP4;2 proteins, members of different KRP classes, were used to study association to and inhibitory activity on different maize cyclin D (CycD)-cyclin-dependent kinase (CDK) complexes.