Conserved Site

S100/Calbindin-D9k, conserved site (IPR001751)

Short name: S100/CaBP-9k_CS


The calcium-binding domain found in S100 and CaBP-9k proteins is a subfamily of the EF-hand calcium-binding domain [PMID: 15284904]. S100s are small dimeric acidic calcium and zinc-binding proteins abundant in the brain, with S100B playing an important role in modulating the proliferation and differentiation of neurons and glia cells [PMID: 15006498]. S100 proteins have two different types of calcium-binding sites: a low affinity one with a special structure, and a 'normal' EF-hand type high-affinity site.

Calbindin-D9k (CaBP-9k) also belong to this family of proteins, but it does not form dimers. CaBP-9k is a cytosolic protein expressed in a variety of tissues. Although its precise function is unknown, it appears to be under the control of the steroid hormones oestrogen and progesterone in the female reproductive system [PMID: 16288660]. In the intestine, CaBP-9k may be involved in calcium absorption by mediating intracellular diffusion [PMID: 12520541].

A number of these proteins are known to bind calcium while others are not. The pattern of this entry spans the region of the EF-hand high affinity site but makes no assumptions on the calcium-binding properties of this site.

GO terms

Biological Process

No terms assigned in this category.

Molecular Function

GO:0005509 calcium ion binding

Cellular Component

No terms assigned in this category.

Contributing signatures

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