In signal transduction or any other molecular biology process, the upstream or downstream is related to the molecular or cellular events that follow a mechanistic and temporal order.
In TNF signaling involved in cell survival pathway the TRADD- associated complex also is known as TNF receptor-associated death domain complex has a second messenger that activates temporally after the cell membrane receptor known as IKK signaling protein that help in numerous downstream pathways.
The process of mitosis generates new cells that are genetically identical to each other. Mitosis helps organisms grow in size and repair damaged tissue.