Insights na geometria de centríolos revelada na criotomografia de centríolos duplos e triplos: mero acaso, fortuita necessidade ou design inteligente?

sexta-feira, agosto 31, 2018

Insights into centriole geometry revealed by cryotomography of doublet and triplet centrioles

Garrett A Greenan, Bettina Keszthelyi, Ronald D Vale, David A Agard Is a corresponding author

University of California, United States; Howard Hughes Medical Institute, United States


The proximal and distal centriole show several major structural differences.


Centrioles are cylindrical assemblies comprised of 9 singlet, doublet, or triplet microtubules, essential for the formation of motile and sensory cilia. While the structure of the cilium is being defined at increasing resolution, centriolar structure remains poorly understood. Here, we used electron cryo-tomography to determine the structure of mammalian (triplet) and Drosophila (doublet) centrioles. Mammalian centrioles have two distinct domains: a 200 nm proximal core region connected by A-C linkers, and a distal domain where the C-tubule is incomplete and a pair of novel linkages stabilize the assembly producing a geometry more closely resembling the ciliary axoneme. Drosophila centrioles resemble the mammalian core, but with their doublet microtubules linked through the A tubules. The commonality of core-region length, and the abrupt transition in mammalian centrioles, suggests a conserved length-setting mechanism. The unexpected linker diversity suggests how unique centriolar architectures arise in different tissues and organisms.