Secretogranin II (Sgll)
is an acidic secretory protein, which was originally designated as chromogranin
C. Sgll retains a number of pairs of basic residues within its amino acid
sequence which are sites at which proteolytic processing could cleave smaller
peptides from the precursor protein. Several peptides cleaved from Sgll are
reported to date, including secretoneurin and EM-66. Secretoneurin, a 33 amino
acid peptide, can be found as immunoreactive fibers throughout the central
nervous system, however, higher concentrations are observed in hypothalamus,
especially in the median eminence. The most important function of secretoneurin
in the central nervous system is the regulation of neurotransmitter systems,
including dopamine release in vitro as well as in vivo. EM-66, a 66 amino acid
peptide has its immunoreactivity in the pituitary anterior lobe, and adrenal
medulla in the rat, suggesting its distinct role in the endocrine system.
However, judging from the putative cleavage sites of the basic residue pairs in
the amino acid sequence of SgII, there remains a possibility that other peptides
are produced by proteolytic processing of Sgll, but have not yet been
investigated. Thus, we sought in this study to investigate the existence of a
novel 40 amino acid peptide processed from Sgll (AA529-568), designated
manserin, in the rat neuroendocrine system. In addition, by comparing cellular
localizations between Sgll and manserin, we aimed to suggest a distinct function
for manserin in the rat.
Aika Yajima et al. Neuroreport. 2004 Aug 6 (15-2):1755-59
