Formin 1 regulates microtubule and F-actin organization to support spermatid transport during spermatogenesis in the rat testis

Document Type

Article (peer-reviewed)

Publication Date



Formin 1 confers actin nucleation by generating long stretches of actin microfilaments to support cell movement, cell shape, and intracellular protein trafficking. Formin 1 is likely involved in microtubule (MT) dynamics due to the presence of a MTB (microtubule binding) domain near its N-terminus. Herein, formin 1 was shown to structurally interact with α-tubulin, the building block of MT, and also EB1 (end binding protein 1, a MT plus(+)-end binding protein that stabilizes MT) in the testis. Knockdown of formin 1 in Sertoli cells with an established tight junction (TJ)-barrier was found to induce down-regulation of detyrosinated MT (a stabilized form of MT), and disorganization of MTs in which MTs were retracted from the cell cortical zone, mediated through a loss of MT polymerization and down-regulation of Ark1/2 signaling kinase. An efficient knockdown of formin 1 in the testis reduced the number of track-like structures conferred by MTs and F-actin considerably, causing defects in spermatid and phagosome transport across the seminiferous epithelium. In summary, formin1 maintains MT and F-actin track-like structures to support spermatid and phagosome transport across the seminiferous epithelium during spermatogenesis.