Regulates ciliary localization of the BBSome complex. Together with the BBSome complex, controls SMO ciliary trafficking and contributes to the sonic hedgehog (SHH) pathway regulation. May play a role in neurite outgrowth. May have tumor suppressor function. Self-associates. Interacts with BBS9; the interaction mediates the association of LZTL1 with the BBsome complex and regulates BBSome ciliary trafficking. Highly expressed in testis. Expressed in brain, cerebellum, eye, heart, kidney, liver, lung and trachea. In small intestine, graded expression along the crypt-villus axis with high levels in the villus apex and lower levels in the crypt stem cells (at protein level). Not expressed in skeletal muscle and white adipose tissue. In hippocampus, up-regulated by exercise training. Belongs to the LZTFL1 family.