In the graph at 4:50, did you perhaps accidentally swap mobile with immobile proteins? It would seem to me that if the ROI recovers its fluorescence close to 100% before photobleaching, it would be due to diffusion of proteins
Could you go into more detail on what's happening in the sides of the fish keratin cell? If not much is known, maybe just an addendum to help define the 'tightly packed network'. Love your explanations :)
The sides of the cell are a lot like the back: actin is disassembled there to promote "pulling in" the sides so the cell moves forward and isn't torn in half! Actin filaments grow at one end and break down at the other end, and they can form branching structures with the help of accessory proteins (notably Arp2/3). Many, many proteins are involved in controlling how fast and where actin forms filaments! This video is just the tip of the iceberg on how actin contributes to cell crawling :)
