Hamartin (Tuberous sclerosis 1 protein) is a 1164 amino acid tumour suppressor coded by the TSC1 gene and deficient in some forms of tuberous sclerosis and FCDBC (focal cortical dysplasia of Taylor balloon cell type). It is a mainly membrane protein that appears to act in:
- Vesicular transport
- Tumour suppression
- Immune response to bacterial infection
The probable common thread is that it negatively regulates the activity of mTOR complex 1 in mTOR signalling. Thus it has essential cell-intrinsic roles in T cell survival, quiescence, and mitochondrial homeostasis.