Core 2 36-GlcNAc-transferase

Unmodified core 1 structures can be converted to branched core 2 structures (Table 1, Figure 2) by core 2 / 6-GlcNAc-transferase (C2GnT) (EC 2.4.1.102). Although the enzyme is expressed in only specific cell types, it is present in most mucin-secreting cells such as those in the intestine and bronchi. In nonmucin-producing... 

Core 2 p6-GlcNAc-transferase (Figure 1) appears to have a number of important functions. The enzyme is altered in leukemia, cancer and upon cell differentiation, and plays important roles in the immune system. The activity appears to be induced in the heart tissue of diabetic rats, in comparison to normal rat hearts [33]. Core 2... 

P6-GlcNAc-transferase activity is regulated during activation of lymphocytes [34], and differentiation of murine and human cancer cells [25, 35], The activity is increased in leukemia cells which are aberrantly differentiated [36, 37] and is abnormal in immunodeficiency disease [38]. Repopulation of SCID mice with bone marrow cells that overexpress core 2 P6-GlcNAc-transferase results in impairment of myeloid differentiation [39]. This indicates that core 2 p6-GlcNAc-transferase is critically involved in the process of differentiation. 

In addition, the bulky core 2 structures may mask the recognition of underlying peptide by antibodies. In breast cancer cells T47D and BT20, mRNA for core 2 P6-GlcNAc-transferase is not expressed [43], thus core 2 structures are not made. As a consequence, peptide epitopes are accessible by antibodies SMS. 

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