Protein kinase Spk1

Function

Protein kinase Spk1 (Rad53) is a yeast serine/threonine protein kinase which phosphorylates proteins on serine, threonine and tyrosine^[1]. Rad53 controls S-phase checkpoint and G1 and G2 DNA damage checkpoints.

Structural highlights

Rad53 contains phosphothreonine (PTO) recognition domains: FHA1 at the N-terminal (residues 1-164) which selects for Asp at position +3 relative to PTO and FHA2 at the C-terminal (residues 573-730) which selects for Ile at position +3 relative to PTO. Two SCD - SQ/TQ-rich cluster domains – are flanking the kinase domain. SCD domain is associated with DNA-damage-response proteins. The yeast FHA1 domain interacts with peptide containing PTOXXD sequence^[2].