Granin

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.

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.

Granin (disambiguation)

Granin could be:

List of characters in the Metal Gear series

The Metal Gear franchise features a large number of characters created by Hideo Kojima and designed by Yoji Shinkawa. Its setting features several soldiers with supernatural powers provided by the new advancements of science.

The series follows mercenary Solid Snake given government missions of finding the Metal Gear weapon, resulting in encounters with Gray Fox and Big Boss in Outer Heaven (Metal Gear) and Zanzibar Land (Metal Gear 2: Solid Snake). Later, Solid Snake meets Otacon and opposes Liquid Snake's FOXHOUND in Metal Gear Solid then assists Raiden in fighting both Solidus Snake and the Patriots in Metal Gear Solid 2: Sons of Liberty. Additionally, there are several prequel games that follows Big Boss's past and legend development as well as the origins of FOXHOUND, Outer Heaven and the Patriots.

While the original Metal Gear games had their characters designs modeled after Hollywood actors, the Metal Gear Solid games established a series of consistent designs based on Shinkawa's ideas of what would appeal to gamers. Additionally, several of the characters he designs follow Kojima and the other staff's ideas. Critical reception of the game's cast has been positive as publications praised their personalities and roles within the series.