KKXX sorting signal,

binds to a complex of the COPI α and β subunits

TLS Online TPP Program

#Id: 10319

#Section 2: General Biology

Fas-L on the cytotoxic T cell binds to its receptor, the Fas protein on the tumor cells, an apoptotic signaling pathway in the tumor cells becomes activated, which also leads to tumor cell death. 

TLS Online TPP Program

#Id: 10320

#Section 2: General Biology

The tumor cells may acquire additional oncogenic mutations that allow them to escape the immune system.

TLS Online TPP Program

#Id: 10321

#Section 2: General Biology

The tumor down regulates the expression of class I MHC proteins

TLS Online TPP Program

#Id: 10322

#Section 2: General Biology

Sometimes the tumor cells up-regulate the expression of anti-apoptotic proteins like BCL-2.

TLS Online TPP Program

#Id: 10323

#Section 2: General Biology

TLS Online TPP Program

#Id: 10324

#Section 2: General Biology

PD-1 has a structure similar to CTLA-4 and when activated negatively regulates T-cell function by inducing apoptosis of activated T cells.