Protein interactions with 14-3-3 show distinct preferences for it’s different isoforms and are regulated by phosphorylation of both 14-3-3 and the bound protein. 14-3-3 tau/theta is primarily expressed in T-cells although it occurs at lower levels in the brain, heart, pancreas placenta and kidneys. It plays a role in cell cycle progression via interaction with p27(Kip1). Along with COPI, the theta isoform binds the GB1 RSR sequence involved in protein trafficking. The isoform forms a complex with Hsp60 and cellular prion protein which may be involved in prion diseases. Elevated levels of 14-3-3 tau/theta are observed in amyotrophic lateral sclerosis. 14-3-3 tau/theta also binds BCR/Abl, bacterial effector protein Tir, yes-associated protein and the FSH receptor.