The Xist transcript is regulated in a negative manner by Tsix, its antisense partner.

TLS Online TPP Program

#Id: 10519

#Unit 4. Cell Communication and Cell Signaling

During apoptosis, increasing amounts of phosphatidylserine are found in the exoplasmic leaflet, where it acts as an “eat me” signal

TLS Online TPP Program

#Id: 10520

#Unit 4. Cell Communication and Cell Signaling

In normal vertebrate cells, ATP-powered phospholipid flippases  (members of the ABC transporter) called 

ATP11A and ATP11C

TLS Online TPP Program

#Id: 10521

#Unit 4. Cell Communication and Cell Signaling

TLS Online TPP Program

#Id: 10522

#Unit 4. Cell Communication and Cell Signaling

In resting cells 

ATP11A and ATP11C, continuously transport phosphatidylserine from the outer to the inner leaflet of the plasma membrane.

TLS Online TPP Program

#Id: 10523

#Unit 4. Cell Communication and Cell Signaling

In resting cells

Phospholipid scramblase XKR8 and TMEM16F would equilibrate phosphatidylserine in both plasma membrane leaflets, is inactive.

TLS Online TPP Program

#Id: 10524

#Unit 4. Cell Communication and Cell Signaling

During apoptosis, caspase-3 cleaves both ATP11A and

ATP11C, inactivating them