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LRIG1 protein in human cells and tissues
Jonas Nilsson1, Anna Starefeldt, Roger Henriksson
1Department of Radiation Sciences, Oncology, Umeå University, SE-90187, Umeå, Sweden.
Cell and Tissue Research
|April 10, 2003
Summary
The human LRIG1 gene encodes an integral cell-surface protein. LRIG1 is expressed in various human tissues and may be cleaved into smaller fragments.
Area of Science:
- Molecular Biology
- Cell Biology
- Genetics
Background:
- The human LRIG1 gene, previously known as LIG1, has been cloned.
- LRIG1 is a predicted integral cell-surface protein with similarities to the Drosophila melanogaster epidermal growth factor receptor antagonist, Kekkon-1.
Purpose of the Study:
- To characterize the LRIG1 protein, including its molecular weight, localization, and tissue expression.
- To investigate potential cleavage of the LRIG1 protein.
Main Methods:
- Peptide antibody generation (LRIG1-151) for protein detection.
- Western blotting under reducing and non-reducing conditions.
- Cell surface biotinylation and confocal microscopy.
- Immunohistochemical analysis of normal human tissues.
Main Results:
- LRIG1 protein exists as 143 kDa and 134 kDa species under reducing conditions, potentially fragmenting into 111 kDa (N-terminal) and 32 kDa (C-terminal) forms.
- Non-reducing conditions revealed LRIG1 monomers and higher molecular weight complexes.
- LRIG1 localizes to the cell surface in ZR-75 and COS-7 cells.
- Immunohistochemistry confirmed LRIG1 expression in epithelia, neurons, and muscles across various human organs.
- Western blotting detected LRIG1 protein in prostate, mammary epithelial cells, ileum, stomach, lung, and cerebral cortex lysates.
Conclusions:
- LRIG1 is an integral cell-surface membrane protein expressed in specific cell types within diverse human tissues.
- The 143 kDa LRIG1 protein may undergo cleavage into 111 kDa and 32 kDa fragments.