Molecular characterisation of ‘transmembrane protein 192’ (TMEM192), a novel protein of the lysosomal membrane
-
Bernd Schröder
Abstract
Transmembrane protein 192 (TMEM192) has been previously identified in proteomic analyses of lysosomal membranes. TMEM192 does not exhibit any significant homology to known protein families and possesses four potential transmembrane segments. To approach the molecular role of TMEM192, a detailed biochemical characterisation of this protein was performed. Expression constructs of fusion proteins containing TMEM192 and appended epitope tags were constructed. In HeLa cells these proteins were detected in membranes of lysosomes/late endosomes. To examine endogenous TMEM192, a TMEM192-specific antibody was generated and validated. With this antibody colocalisation of endogenous TMEM192 with lysosomal and late endosomal markers was demonstrated. Using Percoll density gradient centrifugation and immunoblotting, co-sedimentation of major portions of both TMEM192 and the lysosomal proteins LAMP-2 and cathepsin D into high-density fractions was observed. Interestingly, in contrast to many other lysosomal proteins no N-glycosylation of TMEM192 could be detected. Western blotting of reduced and non-reduced samples and co-immunoprecipitation experiments indicated TMEM192 to be a homodimer with one or more interchain disulphide bridges. TMEM192 was found to be strongly expressed in human kidney, liver, lung and pancreas tissue. The widespread tissue distribution could suggest an important role of TMEM192 for lysosomal function.
©2010 by Walter de Gruyter Berlin New York
Articles in the same Issue
- Guest Editorial
- Highlight: Molecular Neurobiology
- HIGHLIGHT: MOLECULAR NEUROBIOLOGY
- Actin-mediated gene expression in neurons: the MRTF-SRF connection
- RIM proteins and their role in synapse function
- Brain tumor stem cells
- The mitochondria permeability transition pore complex in the brain with interacting proteins – promising targets for protection in neurodegenerative diseases
- Involvement of the calcium sensor GCAP1 in hereditary cone dystrophies
- Live cell imaging of cytoskeletal dynamics in neurons using fluorescence photoactivation
- REVIEWS
- Contributions of the Ah receptor to bilirubin homeostasis and its antioxidative and atheroprotective functions
- Cathepsin L in metastatic bone disease: therapeutic implications
- GENES AND NUCLEIC ACIDS
- Activity-based selection of HIV-1 reverse transcriptase variants with decreased polymerization fidelity
- CELL BIOLOGY AND SIGNALING
- Multiple protective functions of catalase against intercellular apoptosis-inducing ROS signaling of human tumor cells
- Molecular characterisation of ‘transmembrane protein 192’ (TMEM192), a novel protein of the lysosomal membrane
- PROTEOLYSIS
- Functional study of elafin cleaved by Pseudomonas aeruginosa metalloproteinases
Articles in the same Issue
- Guest Editorial
- Highlight: Molecular Neurobiology
- HIGHLIGHT: MOLECULAR NEUROBIOLOGY
- Actin-mediated gene expression in neurons: the MRTF-SRF connection
- RIM proteins and their role in synapse function
- Brain tumor stem cells
- The mitochondria permeability transition pore complex in the brain with interacting proteins – promising targets for protection in neurodegenerative diseases
- Involvement of the calcium sensor GCAP1 in hereditary cone dystrophies
- Live cell imaging of cytoskeletal dynamics in neurons using fluorescence photoactivation
- REVIEWS
- Contributions of the Ah receptor to bilirubin homeostasis and its antioxidative and atheroprotective functions
- Cathepsin L in metastatic bone disease: therapeutic implications
- GENES AND NUCLEIC ACIDS
- Activity-based selection of HIV-1 reverse transcriptase variants with decreased polymerization fidelity
- CELL BIOLOGY AND SIGNALING
- Multiple protective functions of catalase against intercellular apoptosis-inducing ROS signaling of human tumor cells
- Molecular characterisation of ‘transmembrane protein 192’ (TMEM192), a novel protein of the lysosomal membrane
- PROTEOLYSIS
- Functional study of elafin cleaved by Pseudomonas aeruginosa metalloproteinases
