Sub-culturing of cells is also known as:
Sub-culturing termed passaging or splitting involves dissociating cells from confluent culture and seeding at lower density into fresh vessels with new medium to maintain continuous propagation and avoid contact inhibition. As adherent cultures approach 80% confluence, local depletion of nutrients, accumulation of metabolic waste lactate and ammonia, reduction of mitogenic growth factors, and activation of Hippo signaling pathway which excludes YAP from nucleus suppresses cyclin D1 transcription and halts division. Similarly suspension cells experience density-dependent quorum signals slowing
Ref: Freshney Culture of Animal Cells Ch.14 Subculture Passaging; ATCC Subculture Guidelines: contact inhibition and nutrient depletion necessitate passaging.
