Calreticulin affects beta-catenin-associated pathways.
Calreticulin, a Ca(2+) storage protein and chaperone in the endoplasmic reticulum, also modulates cell adhesiveness. Overexpression of calreticulin correlates with (i) increased cell adhesiveness, (ii) increased expression of N-cadherin and vinculin, and (iii) decreased protein phosphorylation on tyrosine. Among proteins that are dephosphorylated in cells that overexpress calreticulin is beta-catenin, a structural component of cadherin-dependent adhesion complexes, a member of the armadillo family of proteins and a part of the Wnt signaling pathway. We postulate that the changes in cell adhesiveness may be due to calreticulin-mediated effects on a signaling pathway from the endoplasmic reticulum, which impinges on the Wnt signaling pathway via the cadherin/catenin protein system and involves changes in the activity of protein-tyrosine kinases and/or phosphatases.
Fadel
M P
MP
Department of Anatomy and Cell Biology, University of Toronto, Toronto, Ontario M5S 1A8, Canada.
Szewczenko-Pawlikowski
M
M
Leclerc
P
P
Dziak
E
E
Symonds
J M
JM
Blaschuk
O
O
Michalak
M
M
Opas
M
M
D000818:Animals; D001483:Base Sequence; D002135:Calcium-Binding Proteins / Q000502:physiology*; D037282:Calreticulin; D002448:Cell Adhesion; D002460:Cell Line; D003598:Cytoskeletal Proteins / Q000737:chemistry / Q000378:metabolism*; D017931:DNA Primers; D004721:Endoplasmic Reticulum / Q000201:enzymology / Q000378:metabolism; D005347:Fibroblasts / Q000378:metabolism; D051379:Mice; D010766:Phosphorylation; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012261:Ribonucleoproteins / Q000502:physiology*; D015398:Signal Transduction; D015534:Trans-Activators; D014443:Tyrosine / Q000378:metabolism; D051176:beta Catenin
C495267:CTNNB1 protein, mouse; D002135:Calcium-Binding Proteins; D037282:Calreticulin; D003598:Cytoskeletal Proteins; D017931:DNA Primers; D012261:Ribonucleoproteins; D015534:Trans-Activators; D051176:beta Catenin; D014443:Tyrosine; D011505:Protein-Tyrosine Kinases; D017027:Protein Tyrosine Phosphatases