Developmental changes in ciliary composition during gametogenesis in Chlamydomonas

Chlamydomonas reinhardtii transitions from mitotically dividing vegetative
cells to sexually competent gametes of two distinct mating types following
nutrient deprivation. Gametes of opposite mating type interact via their
cilia, initiating an intraciliary signaling cascade and ultimately fuse
forming diploid zygotes. The process of gametogenesis is genetically
encoded and a previous study revealed numerous significant changes in mRNA
abundance during this life cycle transition. Here we describe a proteomic
analysis of cilia derived from vegetative and gametic cells of both mating
types in an effort to assess the global changes that occur within the
organelle during this process. We identify numerous membrane and/or
matrix-associated proteins in gametic cilia that were not detected in
cilia from vegetative cells. This includes the pro-protein from which the
GATI-amide gametic chemotactic modulator derives, as well as receptors, a
dynamin-related protein, ammonium transporters, two proteins potentially
involved in the intraciliary signaling cascade-driven increase in cAMP,
and multiple proteins with a variety of interaction domains. These changes
in ciliary composition likely directly affect the functional properties of
this organelle as the cell transitions between life cycle stages.