Chromogranin A/B/C (IPR001990)

Short name: Granin

Overlapping homologous superfamilies


Family relationships


Granins (chromogranins or secretogranins) [PMID: 2053134] are a family of acidic proteins 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 known but they seem to be the precursors of biologically active peptides and/or they may act as helper proteins in the packaging of peptide hormones and neuropeptides. 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, such as:

  • Chromogranin A (CGA): CGA is a protein of about 420 residues; it is the precursor of the peptide pancreastatin which strongly inhibits glucose- induced insulin release from the pancreas.
  • Secretogranin 1 (chromogranin B): A sulfated protein of about 600 residues.
  • Secretogranin 2 (chromogranin C): A sulfated protein of about 650 residues.

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 disulphide bond.

GO terms

Biological Process

No terms assigned in this category.

Molecular Function

No terms assigned in this category.

Cellular Component

GO:0030141 secretory granule

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.