Title : Membrane orientation and subcellular localization of
transmembrane protein 106B (
TMEM106B ), a major risk
factor for frontotemporal lobar degeneration
Abstract :
- TMEM106B was identified as a major risk factor in a genome-wide association study for frontotemporal lobar degeneration (FTLD) with TAR DNA-binding protein ( TDP )-43 pathology
- The most significant association of TMEM106B single nucleotide polymorphisms with risk of FTLD-TDP was observed in patients with progranulin ( GRN ) mutations
- Subsequent studies suggested an inverse correlation between TMEM106B expression and GRN levels in patient serum
- However, in this study, this was not confirmed as we failed to detect a significant alteration of GRN levels upon knockdown or exogenous expression of TMEM106B in heterologous cells
- To provide a basis for understanding TMEM106B function in health and disease, we investigated the membrane orientation and subcellular localization of this completely uncharacterized protein
- By differential membrane extraction and sequential mutagenesis of potential N-glycosylation sites , we identified TMEM106B as a type 2 integral membrane protein with a highly glycosylated luminal domain
- Glycosylation is partially required for the transport of TMEM106B beyond the endoplasmic reticulum to late cellular compartments
- Endogenous as well as overexpressed TMEM106B localizes to late endosomes and lysosomes
- Interestingly, the inhibition of vacuolar H(+)-ATPases significantly increased the levels of TMEM106B , a finding that may provide an unexpected biochemical link to GRN , because this protein is also strongly increased under the same conditions
- Our findings provide a biochemical and cell biological basis for the understanding of the pathological role of TMEM106B in FTLD, an incurable neurodegenerative disorder
Output (sent_index, trigger,
protein,
sugar,
site):
- 6. N-glycosylation, , -, -, sites
- 6. glycosylated, , -, -, domain
Output(Part-Of) (sent_index,
protein,
site):
*Output_Site_Fusion* (sent_index,
protein,
sugar,
site):