Super Amazingly Cool Spindle Assembly Checkpoint (SAC SAC!!)

Hey pretty person! If you are a boy then... take that as you will. I know you're in awe from my fetch title I'll give you a second to calm down. Are you good? Ok, let us begin!

So this article talks about the Spindle Assembly Checkpoint (SAC) and its importance in the cell. So as I'm sure you know meiosis is the process used by germ cells to produce gametes. If you didn't know that then... woe is you. Anyhoo, meiosis consists of meiosis 1 and meiosis 2. Meiosis 1 separates homologous chromosomes and meiosis 2 separates sister chromatids. Here's a picture, as they always make things better.

Now to separate or pull the chromosomes into daughter cells, the cell produces spindle fibers. If the spindle fibers connect to the centromeres of the chromosomes they are called kinetochore spindle fibers, and they are called non-kinetochore spindle fibers if they do not connect to the spindle fibers. If chromosomes are not separated properly, it leads to daughter cells being anupleoid, which will lead to the cell being killed once fertilization has occurred or birth defects in the offspring. Here's a picture showing spindle fibers although I'm hoping you already know what they look like...

In mitosis, SAC exists to ensure that proper chromosome segregation has occurred. In the last decade, most notably in the past several years, researchers have found a checkpoint similar to SAC in meiosis! There is evidence that points to the existence of SAC functions in meiosis. This evidence is provided by studies on many components of SAC. This includes but is not limited to SAC proteins mitotic-arrest deficient-1 (Mad1), Mad2, budding uninhibited by benzimidazole-1 (Bub1), Bub3, BubR1 and Mps1. I was going to be lazy and not list all of them but alas, I shall list them all as it's probably the right thing to do. More componenets include microtubule-kinetochore attachment regulators Ndc80 complex, chromosomal passenger complex, mitotic centromere-associated kinesin (MCAK), kinetochore null 1 (KNL1) and Mis12 complex and spindle stability regulators. So in conclusion, SAC does exist in meiosis but in order to fully understand it and all of its components, more research needs to be done.