Identification of a major keratinocyte cell envelope protein, loricrin.
During epidermal cell cornification, the deposition of a layer of covalently cross-linked protein on the cytoplasmic face of the plasma membrane forms the cell envelope. We have isolated and characterized cDNA clones encoding a major differentiation product of mouse epidermal cells, which has an amino acid composition similar to that of purified cell envelopes. Transcripts of this gene are restricted to the granular layer and are as abundant as the differentiation-specific keratins, K1 and K10. An antiserum against a C-terminal peptide localizes this protein in discrete granules in the stratum granulosum and subsequently at the periphery of stratum corneum cells. Immunofluorescence and immunoelectron microscopy detect this epitope only on the inner surface of purified cell envelopes. Taken together, these results suggest that it is a major component of cell envelopes. On the basis of its presumed function, this protein is named loricrin.
Laboratory of Cellular Carcinogenesis, National Institute of Arthritis, Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, Maryland 20892.
T
T
Mehrel
D
D
Hohl
J A
JA
Rothnagel
M A
MA
Longley
D
D
Bundman
C
C
Cheng
U
U
Lichti
M E
ME
Bisher
A C
AC
Steven
P M
PM
Steinert
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D000831:Animals, Newborn; D000911:Antibodies, Monoclonal / Q000032:analysis; D001483:Base Sequence; D002462:Cell Membrane / Q000032:analysis; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics / Q000302:isolation & purification; D005455:Fluorescent Antibody Technique; D006801:Humans; D015603:Keratinocytes / Q000166:cytology / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics* / Q000302:isolation & purification; D051379:Mice; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D012333:RNA, Messenger / Q000235:genetics; D015183:Restriction Mapping; D014158:Transcription, Genetic
D000596:Amino Acids; D000911:Antibodies, Monoclonal; D008565:Membrane Proteins; D012333:RNA, Messenger; C064554:loricrin; D004247:DNA