HtrA3 is a cellular partner of cytoskeleton proteins and TCP1α chaperonin

Model of the HtrA3 interactions with cytoskeleton proteins and TCP1α chaperonin. Translocation of HtrA3 from mitochondria is accompanied by removal of the N-terminal Mac25 domain [19], resulting in formation of the ΔN-HtrA3L/S proteins. They cleave efficiently vimentin and β-tubulin, and less efficiently- actin; they also stimulate tubulin polymerization. The ΔN-HtrA3S is more active than the ΔN-HtrA3L in the degradation but less active in the polymerization. HtrA3 may act as a co-chaperone, possibly in cooperation with TCP1α, in tubulin polymerization. The HtrA3 influence on the cytoskeleton dynamics may be one of the ways in which this protease/chaperone promotes cell death.77