Flagellar length control in biflagellate eukaryotes: time-of-flight, shared pool, train traffic and cooperative phenomena

Flagella of eukaryotic cells are transient long cylindrical protrusions. Very recently we have developed a stochastic model for flagellar length control based on a time-of-flight (ToF) mechanism. The proteins needed to form and maintain flagella are synthesized in the cell body and transported to the distal tips by Intra-flagellar transport (IFT) trains. We represent the traffic of IFT trains as a totally asymmetric simple exclusion process (TASEP). The ToF mechanism for each flagellum, together with the TASEP-based description of the IFT trains, combined with a scenario of sharing of a common pool of flagellar structural proteins in biflagellates, can account for all key features of experimentally known phenomena. These include ciliogenesis, resorption,  deflagellation as well as regeneration after selective amputation of one of the two flagella. Moreover, we make new predictions on the flagellar length fluctuations and the role of the common pool.