Cloning and
Characterization of a Novel Human Secretory Protein: Secretogranin III
RONG Yi-Ping1£¬2, LIU Feng2, ZENG
Ling-Chun2, MA Wei-Jun2, WEI Dong-Zhi1*, HAN
Ze-Guang2£¬1*
( 1Research
Institute of Biochemistry, State Key Laboratory of Bioreactor Engineering, East
China University of Science and Technology, Shanghai 200237, China; 2Chinese
National Human Genome Center, Shanghai 201203, China )
Abstract We have
cloned a new member of the granin family, termed human secretogranin III
(SgIII), that encodes 468 amino acid residues. The human SgIII protein
possesses an N-terminal signal peptide, seven dibasic sites, and the repeated
DSTK sequences. These structure characteristics are similar to other members of
secretogranin family. The human SgIII has homologous proteins in mouse, rat,
and Xenopus laevis. Genomic organization shows the gene includes 12
coding exons spanning 39 kb of genomic DNA on the human chromosome 15. Human
SgIII is expressed widely as showed in Northern blot and its cDNA hybridizes to
2.2 kb and 1.9 kb bands in many tissues, with two additional 4.5 kb and 3.3 kb
bands in brain. Subcelluar localization and immunoblotting indicated SgIII was
secreted out of cell through trans-Golgi network (TGN). SgIII may take effect
in the biogenesis of secretory granules as a helper protein and be involved in
the production or release of peptide hormones in the regulated secretory
pathway.
Key words secretory protein; secretory granule;
secretogranin III
*Corresponding authors: HAN
Ze-Guang: Tel, 86-21-50801325; Fax, 86-21-50800402; e-mail, [email protected]; WEI Dong-Zhi: Tel, 86-21-64250068;
Fax, 86-21-64250068; e-mail, dzhwei@ecust.edu.cn