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Identification and characterization of a cell surface proteoglycan on keratinocytes

J G Haggerty1, R H Bretton, L M Milstone

  • 1Dermatology Service, VA Medical Center, West Haven, CT 06516.

The Journal of Investigative Dermatology
|October 1, 1992
PubMed

Insights

Researchers identified a new epidermal intercellular proteoglycan, named epican, on human keratinocytes. This proteoglycan is located in the intercellular space and may play a role in cell-cell adhesion.

Area of Science:

  • Dermatology
  • Cell Biology
  • Biochemistry

Background:

  • Proteoglycans are crucial components of the extracellular matrix, filling the intercellular space between keratinocytes.
  • The precise structure and function of intercellular proteoglycans in the epidermis remain largely uncharacterized.

Purpose of the Study:

  • To identify and characterize a novel intercellular proteoglycan expressed by human keratinocytes.
  • To investigate the localization and potential function of this newly identified proteoglycan.

Main Methods:

  • Generation of monoclonal antibodies (MoAb) against keratinocyte proteoglycans.
  • Western blot analysis and deglycosylation to determine protein size and composition.
  • Immunofluorescence microscopy to localize the proteoglycan in epidermal tissue and cultured keratinocytes.

Main Results:

  • A novel intercellular proteoglycan, named epican (epidermal intercellular proteoglycan), was identified and partially characterized.
  • Epican possesses a core protein of approximately 180 kDa and is substituted with heparan sulfate or chondroitin sulfate.
  • Immunofluorescence localized epican to the intercellular spaces of the epidermis and keratinocyte surfaces, particularly at cell-cell contacts.
  • Epican is distinct from syndecan and appears to be a member of the CD44 family of proteoglycans.

Conclusions:

  • Epican is a novel epidermal intercellular proteoglycan found on human keratinocytes.
  • Its localization suggests a role in cell-cell interactions within the epidermis.
  • Epican represents a new member of the CD44 family, expanding our understanding of skin proteoglycan diversity.

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