FIGURE 1.

Potential ways in which LRRK2 and α-synuclein act in PD. (A) LRRK2 and α-synuclein affect each other through a direct physical interaction. (B) LRRK2 and α-synuclein affect each other through an indirect physical interaction in which a mediator(s), such as a molecular chaperone(s), links the two proteins. (C) Both LRRK2 and α-synuclein act synergistically on targets within the same molecular pathway without interacting with each other. (D) LRRK2 and α-synuclein do not interact at all and each affect targets in distinct molecular pathways.