Growth suppressor that facilitates the entry of the cell into cell cycle arrest. Functionally similar to the retinoblastoma protein it binds to and represses the activity of cell-cycle-promoting proteins such as SV40 large T antigen, adenovirus E1A, and the transcription factor E2F. Necdin also interacts with p53 and works in an additive manner to inhibit cell growth. Also functions as a transcription factor and directly binds to specific guanosine-rich DNA sequences. Binds to the transactivation domains of E2F1 and p53. Binds also SV40 large T antigen and adenovirus E1A. Interacts with nucleobindin 1 and 2. Mainly cytoplasmic. Translocates to the nucleus where it is found associated with the nuclear matrix. Brain specific. Not detected in other tissues. Expressed in postmitotic neurons. In adult brain the highest expression is in hypothalamus. Highly expressed in thalamus and midbrain. Relatively low levels are in cerebral cortex, hippocampus, striatum, olfactory bulb, cerebellum, pons and spinal cord. Also detected in neurally differentiated embryonal carcinoma cells. Expression levels were high during embryonic and neonatal periods (14 dpc to P7) and decreased thereafter.