Cloning and Expression of Secretagogin, a Novel Neuroendocrine- and Pancreatic Islet of Langerhans-specific Ca2+-binding Protein

Abstract

We have cloned a novel pancreatic beta cell and neuroendocrine cell-specific calcium-binding protein termed secretagogin. The cDNA obtained by immunoscreening a human pancreatic cDNA library using the recently described murine monoclonal antibody D24 contains an open reading frame of 828 base pairs. This codes for a cytoplasmic protein with six putative EF finger hand calcium-binding motifs. The gene could be localized to chromosome 6 by alignment with GenBank genomic sequence data. Northern blot analysis demonstrated abundant expression of this protein in the pancreas and to a lesser extent in the thyroid, adrenal medulla, and cortex. In addition it was expressed in scant quantity in the gastrointestinal tract (stomach, small intestine, and colon). Thyroid tissue expression of secretagogin was restricted to C-cells. Using a sandwich capture enzyme-linked immunosorbent assay with a detection limit of 6.5 pg/ml, considerable amounts of constitutively secreted protein could be measured in tissue culture supernatants of stably transfected RIN-5F and dog insulinoma (INS-H1) cell clones; however, in stably transfected Jurkat cells, the protein was only secreted upon CD3 stimulation. Functional analysis of transfected cell lines expressing secretagogin revealed an influence on calcium flux and cell proliferation. In RIN-5F cells, the antiproliferative effect is possibly due to secretagogin-triggered down-regulation of substance P transcription.

Hypothalamic CNTF volume transmission shapes cortical noradrenergic excitability upon acute stress

“…Finally, we tested whether mPFC‐targeting NE neurons respond to CNTF by injecting AAVs encoding the Ca 2+ indicator GCaMP6 in a Cre‐dependent manner into the PFC (Fig 3G). For this, we have developed secretagogin ( Scgn )‐Cre mice (Appendix Fig S2D and D1) because secretagogin, an EF‐hand tetra‐Ca 2+ ‐sensor protein (Wagner et al , 2000; Alpár et al , 2012; Romanov et al , 2015), is abundantly expressed in NE neurons residing in LC (Mulder et al , 2009). Fourteen days after viral GCaMP6 delivery, we used Ca 2+ imaging to monitor whether CNTF superfusion affects NE neurons ex vivo .…”

Oxidative Stress in the Hypothalamus: the Importance of Calcium Signaling and Mitochondrial ROS in Body Weight Regulation

“…Secretagogin (Scgn) is a recently described CBP cloned from pancreatic (-cells and endocrine cells of the gastrointestinal tract [79]. Scgn is a member of the EF-hand family of CBPs containing 3D –motif to bind Ca 2+ in the cytosol.…”

Secretagogin is Expressed by Developing Neocortical GABAergic Neurons in Humans but not Mice and Increases Neurite Arbor Size and Complexity

“…SCGN encodes a calcium-binding protein that was first discovered as a modifier of insulin release in pancreatic β cells (Wagner et al 2000). Scgn expression has been reported in a variety of neuronal subtypes in mammalian brains (Mulder et al 2009(Mulder et al , 2010) (further reviewed in Alpar et al 2012), but its cellular origins in prenatal human brain have not been described.…”