Structural requirements for the specific binding of CRABP2 to cyclin D3

Martyna W Pastok; Charles W E Tomlinson; Shannon Turberville; Abbey M Butler; Arnaud Baslé; Martin E M Noble; Jane A Endicott; Ehmke Pohl; Natalie J Tatum

doi:10.1016/j.str.2024.09.020

Structural requirements for the specific binding of CRABP2 to cyclin D3

Structure. 2024 Oct 16:S0969-2126(24)00389-7. doi: 10.1016/j.str.2024.09.020. Online ahead of print.

Authors

Martyna W Pastok¹, Charles W E Tomlinson², Shannon Turberville³, Abbey M Butler², Arnaud Baslé⁴, Martin E M Noble³, Jane A Endicott⁵, Ehmke Pohl⁶, Natalie J Tatum⁷

Affiliations

¹ Newcastle University Centre for Cancer, Translational and Clinical Research Institute, Newcastle University, Paul O'Gorman Building, Framlington Place, Newcastle upon Tyne NE2 4HH, UK. Electronic address: [email protected].
² Department of Chemistry, Durham University, Lower Mountjoy, South Road, Durham DH1 3LE, UK.
³ Newcastle University Centre for Cancer, Translational and Clinical Research Institute, Newcastle University, Paul O'Gorman Building, Framlington Place, Newcastle upon Tyne NE2 4HH, UK.
⁴ Biosciences Institute, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK.
⁵ Newcastle University Centre for Cancer, Translational and Clinical Research Institute, Newcastle University, Paul O'Gorman Building, Framlington Place, Newcastle upon Tyne NE2 4HH, UK. Electronic address: [email protected].
⁶ Department of Chemistry, Durham University, Lower Mountjoy, South Road, Durham DH1 3LE, UK; Department of Biosciences, Durham University, Upper Mountjoy, South Road, Durham DH1 3LE, UK.
⁷ Newcastle University Centre for Cancer, Translational and Clinical Research Institute, Newcastle University, Paul O'Gorman Building, Framlington Place, Newcastle upon Tyne NE2 4HH, UK. Electronic address: [email protected].

PMID: 39419021
DOI: 10.1016/j.str.2024.09.020

Abstract

Cellular retinoic acid binding protein 2 (CRABP2) transports retinoic acid from the cytoplasm to the nucleus where it then transfers its cargo to retinoic acid receptor-containing complexes leading to activation of gene transcription. We demonstrate using purified proteins that CRABP2 is also a cyclin D3-specific binding protein and that the CRABP2 cyclin D3 binding site and the proposed CRABP2 nuclear localization sequence overlap. Both sequences are within the helix-loop-helix motif that forms a lid to the retinoic acid binding pocket. Mutations within this sequence that block both cyclin D3 and retinoic acid binding promote formation of a CRABP2 structure in which the retinoic acid binding pocket is occupied by an alternative lid conformation. Structural and functional analysis of CRABP2 and cyclin D3 mutants combined with AlphaFold models of the ternary CDK4/6-cyclin D3-CRABP2 complex supports the identification of an α-helical protein binding site on the cyclin D3 C-terminal cyclin box fold.

Keywords: ATRA; CDK4; CDK6; CRABP2; alphafold; cyclin; regulation; retinoic acid.