TNF and plasma cell myeloma: Since TNF-α has been shown to vary significantly phosphorylation of p65 at Ser 536 in the transactivation domain (TAD) compared to Thr 254, Ser 276, Ser 311, and Ser 529 in a variety of cell types [23], we chose to detect phosphorylation of p65 at Ser 536 in myeloma cells.