Details

Autor(en) / Beteiligte

• Grütter, Christian
• Sreeramulu, Shivakumar
• Sessa, Guido
• Rauh, Daniel

Titel

Structural Characterization of the RLCK Family Member BSK8: A Pseudokinase with an Unprecedented Architecture

Ist Teil von

• Journal of molecular biology, 2013-11, Vol.425 (22), p.4455-4467

Ort / Verlag

England: Elsevier Ltd

Erscheinungsjahr

2013

Quelle

Access via ScienceDirect (Elsevier)

Beschreibungen/Notizen

• Brassinosteroid signaling kinases (BSKs) are plant-specific receptor-like cytoplasmic protein kinases involved in the brassinosteroid signaling pathway. Unlike common protein kinases, they possess a naturally occurring alanine residue at the “gatekeeper” position, as well as other sequence variations. How BSKs activate downstream proteins such as BSU1, as well as the structural consequences of their unusual sequential features, was unclear. We crystallized the catalytic domain of BSK8 and solved its structure by multiple-wavelength anomalous dispersion phasing methods to a resolution of 1.5Å. In addition, a co-crystal structure of BSK8 with 5-adenylyl imidodiphosphate (AMP-PNP) revealed unusual conformational arrangements of the nucleotide phosphate groups and catalytic key motifs, typically not observed for active protein kinases. Sequential analysis and comparisons with known pseudokinase structures suggest that BSKs represent constitutively inactive protein kinases that regulate brassinosteroid signal transfer through an allosteric mechanism. [Display omitted] •First insights into the structural architecture of a BSK family member.•Identification of unusual conformational arrangements within the active site.•Structural and sequence comparisons imply that BSKs are pseudokinases.•Activity test reveal that BSKs are catalytically inactive protein kinases.