1.A.139. The Chromogranin-B/Secretogranin-1 (CB/S1) Family Chloride loaders and extruders are expressed in both cell surfaces and intracellular membranes. Large-conductance, highly selective Cl^-channels, formed by membrane-bound chromogranin B (CHGB), which differs from all other known anion channels of conventional transmembrane topology, and is distributed in plasma membranes, endomembrane systems, endosomal, and endolysosomal compartments. Jiang and Yadav 2022 discussed the potential physiological importance of the CHGB channels to Cl- homeostasis, cellular excitability and volume control as well as cation uptake and release at the cellular and subcellular levels.
References:
Jiang, Q.X. and G. Yadav. (2022). The mechanisms of chromogranin B-regulated Cl^- homeostasis. Biochem Soc Trans 50: 1659-1672.
Examples:
TC#	Name	Organismal Type	Example
1.A.139.1.1	Chromogranin B (CHGB), also called secretogranin-1 (SCG1) (677 aas with 1 or 2 N-terminal TMSs), is a large conductance chloride channel present in mammals (Jiang and Yadav 2022). See the family description for details about its enzymatic catalytic activities.		CHGB of Homo sapiens

1.A.139.1.2	Protein Aster-C or GRAM domain-containing protein 1C of 717 aas and 1 N-terminal TMS.		*Aster-C of Alosa sapidissima* (American shad)**

1.A.139.1.3	Secretogranin-1 of 676 aas and 1 N-terminal TMS.		*GRAMD1C of Cheilinus undulatus* (humphead wrasse)**

1.A.139.1.4	Secretogranin-1 of 617 aas and 1 N-terminal TMS.		*Secretogranin of Anguilla anguilla* (European eel)**

1.A.139.1.5	Chromogranin-A of 617 aas and 1 N-terminal TMS.		*Chromogranin-A of Dromaius novaehollandiae,* emu**