TMEM106B
Function
In neurons, involved in the transport of late endosomes/lysosomes (PubMed:25066864). May be involved in dendrite morphogenesis and maintenance by regulating lysosomal trafficking (PubMed:25066864). May act as a molecular brake for retrograde transport of late endosomes/lysosomes, possibly via its interaction with MAP6 (By similarity). In motoneurons, may mediate the axonal transport of lysosomes and axonal sorting at the initial segment (By similarity). It remains unclear whether TMEM106B affects the transport of moving lysosomes in the anterograde or retrograde direction in neurites and whether it is important in the sorting of lysosomes in axons or in dendrites (By similarity). In neurons, may also play a role in the regulation of lysosomal size and responsiveness to stress (PubMed:25066864). Required for proper lysosomal acidification (By similarity).
(Microbial infection) Plays a role in human coronavirus SARS-CoV-2 infection, but not in common cold coronaviruses HCoV-229E and HCoV-OC43 infections. Involved in ACE2-independent SARS-CoV-2 cell entry. Required for post-endocytic stage of virus entry, facilitates spike-mediated membrane fusion. Virus attachment and endocytosis can also be mediated by other cell surface receptors.
Involvement in disease
Ubiquitin-positive frontotemporal dementia
UP-FTD
Frontotemporal dementia (FTD) is the second most common cause of dementia in people under the age of 65 years. It is an autosomal dominant neurodegenerative disease.
None
The gene represented in this entry acts as a disease modifier. Risk alleles confer genetic susceptibility by increasing gene expression (PubMed:20154673, PubMed:21178100). Increased expression may be the result of down-regulation of microRNA miR-132 and miR-212, that repress TMEM106B expression (PubMed:22895706). Thr-185 is a risk allele associated with lower GRN protein levels and early age at onset in GRN UP-FTD mutation carriers: it presents slower protein degradation that leads to higher steady-state TMEM106B levels, leading to alterations in the intracellular versus extracellular partitioning of GRN (PubMed:23742080).
Frontotemporal dementia and/or amyotrophic lateral sclerosis 1
FTDALS1
An autosomal dominant neurodegenerative disorder characterized by adult onset of frontotemporal dementia and/or amyotrophic lateral sclerosis in an affected individual. There is high intrafamilial variation. Frontotemporal dementia is characterized by frontal and temporal lobe atrophy associated with neuronal loss, gliosis, and dementia. Patients exhibit progressive changes in social, behavioral, and/or language function. Amyotrophic lateral sclerosis is characterized by the death of motor neurons in the brain, brainstem, and spinal cord, resulting in fatal paralysis.
None
The gene represented in this entry acts as a disease modifier.
Leukodystrophy, hypomyelinating, 16
HLD16
An autosomal dominant disorder characterized by hypomyelination, leukodystrophy, and thin corpus callosum observed on brain imaging. Clinical features include hypotonia, nystagmus, and mildly delayed motor development with onset in infancy, ataxic or broad-based gait, hyperreflexia, intention tremor, dysmetria, and a mild pyramidal syndrome. Some patients have cognitive impairment, whereas others may have normal cognition or mild intellectual disability with speech difficulties.
None
The disease may be caused by variants affecting the gene represented in this entry.
A TMEM106B truncated C-terminal fragment (residues 120 through 254) was found to aggregate into stable amyloid fibrils in the brain of patients suffering from diverse genetic and sporadic tauopathies, amyloid-beta amyloidoses, synucleinopathies and TDP-43 proteinopathies. It is currently unclear whether TMEM106B fibrils are associated with a pathogenic process or represents a non-specific secondary phenomenon, a general downstream marker of lysosomal stress for instance (PubMed:35247328, PubMed:35344984, PubMed:35344985). TMEM106B amyloid filaments form in an age-dependent manner in human brains, however fibrillization of TMEM106B seems substantially greater in patients with known neurodegeneration compared to age-matched unaffected individuals (PubMed:35344985).
Sequence Similarities
Belongs to the TMEM106 family.
Tissue Specificity
Expressed in the brain, including in the frontal cortex (at protein level) (PubMed:35247328, PubMed:35344985). Expressed in lung epithelial cells (PubMed:33686287).
Cellular localization
- Late endosome membrane
- Single-pass type II membrane protein
- Lysosome membrane
- Single-pass type II membrane protein
- Cell membrane
- Single-pass type II membrane protein
- Colocalizes with LAMP1. A small fraction resides on the cell surface (PubMed:37421949).
Alternative names
Transmembrane protein 106B, TMEM106B