Fig 7. Mek1 inhibits Rad51 activity in dmc1Δ diploids by phosphorylation of both Rad54 and Hed1.

(A) In the absence of DMC1, active Mek1 phosphorylates both Rad54 and Hed1, as well as itself. Rad54-Rad51 complex formation and strand invasion activity are prevented because phosphorylated Rad54 has decreased affinity for Rad51 and Hed1 bound to Rad51 excludes Rad54. Mek1 remains constitutively active by autophosphorylation. This is a cartoon and not meant to indicate any particular stoichometries between the proteins. (B) Inactivation of Mek1 results in degradation of Hed1 and dephosphorylation of Rad54, thereby allowing Rad51-Rad54 complex formation and DSB repair.