Annexin I and involucrin are cross-linked by particulate transglutaminase into the cornified cell envelope of squamous cell carcinoma Y1.
The squamous cell carcinoma line, SqCC/Y1, like natural squamous epithelia, forms a cornified cell envelope during differentiation which can be directly correlated with an increase in particulate transglutaminase activity. When transglutaminase is activated in these cells by calcium ionophore X-537A, annexin I and involucrin become incorporated into the cornified cell envelope and cannot be extracted with solutions containing sodium dodecyl sulfate (SDS) and beta-mercaptoethanol. This effect is specific for annexin I; thus, the amounts of annexins II and IV that were extractable from cells by SDS and beta-mercaptoethanol did not change following treatment with ionophore X-537A. Annexin I could be cross-linked in vitro to itself and to other endogenous proteins by transglutaminase extracted from the particulate fraction of SqCC/Y1 cells. Immunofluorescence studies showed that cross-linked annexin I and involucrin form an envelope-like structure in SqCC/Y1 cells during differentiation that cannot be extracted by EGTA and Triton X-100. The amount of staining of this envelope structure corresponded directly to the particulate transglutaminase activity of these cells. Annexin I monoclonal and polyclonal antibodies were shown to bind to purified cornified cell envelopes from SqCC/Y1. These studies suggest that particulate transglutaminase regulates a function of annexin I during the differentiation of SqCC/Y1 cells by covalently cross-linking this protein into the cornified cell envelope.
Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06510.
K G
KG
Moore
A C
AC
Sartorelli
D017302:Annexins; D000906:Antibodies; D002135:Calcium-Binding Proteins / Q000737:chemistry*; D002294:Carcinoma, Squamous Cell / Q000737:chemistry*; D002454:Cell Differentiation; D004790:Enzyme Induction; D008565:Membrane Proteins / Q000032:analysis; D008856:Microscopy, Fluorescence; D011498:Protein Precursors / Q000737:chemistry*; D011503:Transglutaminases / Q000096:biosynthesis / Q000737:chemistry*
D017302:Annexins; D000906:Antibodies; D002135:Calcium-Binding Proteins; D008565:Membrane Proteins; D011498:Protein Precursors; C032253:involucrin; D011503:Transglutaminases