Differentiative changes in fucosyltransferase activity in newborn rat epidermal cells

Area of Science:

• Biochemistry
• Dermatology
• Glycobiology

Background:

• Epidermal basal cells undergo differentiation, a process involving changes in cell surface glycoproteins.
• Lectin-binding specificity of these glycoproteins changes during differentiation, but the underlying enzymatic mechanisms are not fully understood.

Purpose of the Study:

• To identify and characterize enzymatic activity involved in altering glycoprotein lectin-binding specificity in newborn rat cutaneous epidermis.
• To investigate the role of fucosyltransferase in epidermal cell differentiation.

Main Methods:

• Isolation of the membranous fraction from newborn rat cutaneous epidermis.
• Assay of enzymatic activity catalyzing the transfer of L-fucose from GDP-L-fucose to specific glycoprotein acceptors.
• Analysis of changes in lectin-binding specificity using Griffonia simplicifolia Isolectin I-B4 (GS I-B4) and Ulex europeus Agglutinin I (UEA).

Main Results:

• A fucosyltransferase activity was identified in the membranous fraction of newborn rat epidermis.
• This enzyme transfers L-fucose to a glycoprotein associated with basal cells, altering its lectin-binding specificity from GS I-B4 to UEA.
• A second membraneous fucosyltransferase capable of using asialofetuin as an acceptor was also detected.

Conclusions:

• The identified fucosyltransferase plays a key role in modifying epidermal cell surface glycoproteins during differentiation.
• This enzymatic activity is likely responsible for the observed shift in lectin-binding specificity during epidermal basal cell differentiation.
• The presence of multiple membraneous fucosyltransferases suggests complex regulatory mechanisms in epidermal glycosylation.