There are 27 of these repeats in the yeast Pol II CTD, 32 in the worm Caenorhabditis elegans, 45 in the fly Drosophila, and 52 in humans. 

YSPTSPS repeats in CTD corresponds to the complexity of the genome.

TLS Online TPP Program

#Id: 8934

#Unit 2. Cellular Organization

Spindle assembly checkpoint pathway is active until every single kinetochore has attached properly to spindle microtubules

TLS Online TPP Program

#Id: 8935

#Unit 2. Cellular Organization

TLS Online TPP Program

#Id: 8936

#Unit 2. Cellular Organization

When a kinetochore is unattached, the outer kinetochore component Knl1 is phosphorylated by the checkpoint kinase Mps1.

TLS Online TPP Program

#Id: 8937

#Unit 2. Cellular Organization

Phosphorylated Knl1 binds the checkpoint protein kinase Bub1-Bub3 and checkpoint protein BubR1. These three proteins, recruit the Mad1-Mad2 complex to the kinetochore.

TLS Online TPP Program

#Id: 8938

#Unit 2. Cellular Organization

The Mad1-Mad2 complex bound to a kinetochore adopts the active closed form (Mad2-C) and has the ability to convert inactive open Mad2 (Mad2-O) in the cytoplasm into active closed Mad2 is able to inhibit APC/Ccdc²⁰

TLS Online TPP Program

#Id: 8939

#Unit 2. Cellular Organization

checkpoint factors Bub1-Bub3, BubR1 and Mad2-C Together, these proteins form the mitotic checkpoint complex