Chromogranins from Cell Biology to Physiology and Biomedicine

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peptides based on potential cleavage sites at paired basic residues in CgA as shown

in Fig. 2B (Koshimizu et al. 2011b; Loh et al. 2012b). Based on the HPLC profile of

the serpinin peptides in the medium, an earlier peak which eluted in the approximate

position of serpinin with the RRG extension in the C-terminus (serpinin- RRG) was

also present, suggestive of the presence of this peptide. Studies thus far have only

A.

B.

C.

Signal

peptide

(-18-1)

bCgA

SS KK KR KKKKKR KR KR RR KKRRRR

N-terminal sorting

domain (1-115)

C-terminal

domain

for sorting

in GH4C1 cells

(341-431)

SgIII-

binding

doamin

(48-111)

Fig. 2 Schematic of the bovine chromogranin A (bCgA) protein and processing of mCgA at its
C-terminus. (A) bCgA is a 431 amino acid protein with multiple paired and single basic-residue
cleavage sites (K, lysine, R, arginine) that can be used for processing bCgA into smaller peptides
by prohormone convertases (From Loh et al. 2012b). (B) Schematic representation of the synthetic
pathway of mouse pGlu-serpinin (From Koshimizu et al. 2011b). (C) Sequence of C-terminus of
CgA from human, bovine and mouse. Note that the serpinin sequence (in red) differs by 4 amino
acids (underlined) between mouse, human and bovine

Y. PengfiLoh et al.