Late adaptors

Clathrin-coated vesicles mediate transport within the late secretory and the endocytic pathways. Their major coat constituents are clathrin and various adaptor complexes. 

Several groups have shown that SHP-2 and SHP-1 are C-terminally phosphory-lated on two tyrosine residues but the function of these phosphorylation events is controversial. One model is that these phosphorylation events may recruit SH2 domain containing adaptor proteins such as Grb2. Another model is that they may modulate the activity of the enzymes. To address these problems, EPL was employed to incorporate the phosphonate analogs Pmp or F2Pmp at the sites of modification. Semisynthetic proteins containing one or two phosphonates at the physiologic sites were prepared [24, 27, 28]. 

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