Intraflagellar Transport (IFT) and Sperm Formation.

Intraflagellar transport (IFT) is a conserved mechanism for cilia formation. Twenty-two IFT components form the IFT-A complex (six components) and IFT-B complex (sixteen components). Driven by kinesin and dynein motor proteins, these IFT complexes are involved in the trafficking of proteins needed for cilia assembly by anterograde transport and retrograde transport. IFT core components also associate with other proteins for cilia formation. Mutations in IFT core components result in ciliogenesis defects and human diseases, including male infertility. Sperm flagella are specialized motile cilia that not only have core axoneme structure but also possess accessory structures. IFT is required to assemble these structures to form functional sperm. This summary highlights the regulatory roles of specific IFT proteins in spermatogenesis. A deeper understanding of IFT-related mechanisms can shed light on the etiology and pathophysiology of certain male infertility cases, as well as provide insights for the development of novel male contraceptives.