Granin

Granin (chromogranin or secretogranin)
Structure of SS-cyclized catestatin fragment from chromogranin A.[1]
Identifiers
Symbol	Granin
Pfam	PF01271
InterPro	IPR001990
PROSITE	PDOC00365
SCOP	1cfk
SUPERFAMILY	1cfk
OPM superfamily	328
OPM protein	1lv4
Available protein structures: Pfam structures PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

Granin (chromogranin and secretogranin) is a protein family of regulated secretory proteins ubiquitously found in the cores of amine and peptide hormone and neurotransmitter dense-core secretory vesicles.^[2]

Function

Granins (chromogranins or secretogranins) are acidic proteins and are present in the secretory granules of a wide variety of endocrine and neuro-endocrine cells. The exact function(s) of these proteins is not yet settled but there is evidence that granins function as pro-hormones, giving rise to an array of peptide fragments for which autocrine, paracrine, and endocrine activities have been demonstrated in vitro and in vivo. The intracellular biochemistry of granins includes binding of Ca²⁺, ATP and catecholamines (epinephrine, norepinephrine) within the hormone storage vesicle core. There is also evidence that CgA, and perhaps other granins, regulate the biogenesis of dense-core secretory vesicles and hormone sequestration in neuroendocrine cells.

Structure

Apart from their subcellular location and the abundance of acidic residues (Asp and Glu), these proteins do not share many structural similarities. Only one short region, located in the C-terminal section, is conserved in all these proteins. Chromogranins and secretogranins together share a C-terminal motif, whereas chromogranins A and B share a region of high similarity in their N-terminal section; this region includes two cysteine residues involved in a disulfide bond.

Members

Chromogranins

• chromogranin A (CgA)
• chromogranin B (CgB)

chromogranin A (parathyroid secretory protein 1) Identifiers Symbol CHGA Alt. symbols CGA Entrez 1113 HUGO 1929 OMIM 118910 RefSeq NM_001275 UniProt P10645 Other data Locus Chr. 14 q32

chromogranin B (secretogranin 1) Identifiers Symbol CHGB Alt. symbols SCG1 Entrez 1114 HUGO 1930 OMIM 118920 RefSeq NM_001819 UniProt P05060 Other data Locus Chr. 20 pter-p12

Secretogranins

• secretogranin II (SgII) (see also secretoneurin)
• secretogranin III (SgIII)
• secretogranin V (SgV)

secretogranin II (chromogranin C) Identifiers Symbol SCG2 Alt. symbols CHGC, SgII Entrez 7857 HUGO 10575 OMIM 118930 RefSeq NM_003469 UniProt P13521 Other data Locus Chr. 2 q35-q36

secretogranin III (FLJ90833) Identifiers Symbol SCG3 Alt. symbols SGIII Entrez 29106 HUGO 13707 OMIM 611796 RefSeq NM_013243 UniProt Q8WXD2 Other data Locus Chr. 15 q21.3

secretogranin V (7B2 protein) Identifiers Symbol SCG5 Alt. symbols SGNE1 Entrez 6447 HUGO 10816 OMIM 173120 RefSeq NM_003020 UniProt P05408 Other data Locus Chr. 15 q13-q14

Two other proteins (secretogranin IV and VI) are also proposed to belong to the granins on the basis of their physico-chemical properties.

References

1. Preece NE, Nguyen M, Mahata M, et al. (April 2004). "Conformational preferences and activities of peptides from the catecholamine release-inhibitory (catestatin) region of chromogranin A". Regul. Pept. 118 (1-2): 75–87. doi:10.1016/j.regpep.2003.10.035. PMID 14759560.
2. Huttner WB, Gerdes HH, Rosa P (January 1991). "The granin (chromogranin/secretogranin) family". Trends Biochem. Sci. 16 (1): 27–30. doi:10.1016/0968-0004(91)90012-K. PMID 2053134.

External links

• Chromogranins at the US National Library of Medicine Medical Subject Headings (MeSH)

This article incorporates text from the public domain Pfam and InterPro IPR001990