TripletMikrotubuli

TripletMikrotubuli, also known as triplet microtubules, are the structural units that form centrioles and basal bodies. In most animal cells, a centriole is a short, cylindrical organelle built from nine triplets arranged in a ring around a central axis, giving the structure ninefold symmetry.

Each triplet contains three microtubules designated A, B, and C. The A-tubule is a complete microtubule with 13 protofilaments. The B- and C-tubules are incomplete and share their protofilaments with the adjacent tubules (the B-tubule shares with the A-tubule, the C-tubule shares with the B-tubule). The triplets are linked by interacting proteins that stabilize the cylinder, and the centriole is surrounded by pericentriolar material that nucleates microtubules.

Functions of centrioles include organizing the centrosome and spindle apparatus during mitosis, as well as acting as basal bodies that nucleate cilia and flagella. This dual role supports proper chromosome segregation in cell division and the formation of motile or sensory cellular structures.

Centriole duplication occurs once per cell cycle. A daughter centriole forms orthogonally to the mother centriole, guided by a cartwheel scaffold whose core components, such as SAS-6, establish the ninefold symmetry of the new triplet arrangement.

Defects in centriole number or function can impair chromosome segregation and ciliogenesis, contributing to developmental disorders and ciliopathies.