title: Face-to-face, pak-to-pak.
abstract: Biochemical and structural studies of p21-activated kinase 1 (Pak1) by Wang and colleagues in this issue of Structure reveal the structural basis for Pak1 trans-autophosphorylation of the activation loop, a critical step in the activation of kinases.
authors.affiliation: Cancer Biology Program, Fox Chase Cancer Center, 333 Cottman Avenue, Philadelphia, PA 19111, USA.
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Malecka
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Peterson