OCM

Fig1. Designated genetic interval of DFNB90 and other DFNB/DFNA genes and loci on chromosome 7.

What is OCM protein?

Oncomodulin (OCM), an isoform of α-parvalbumin originally discovered in a rat hepatoma, is limited to outer hair cells (OHCs) and also found in macrophages. Oncomodulin is an 11.7 kDa Ca2+-binding protein that was named on the basis of its expression in several tumors and its limited resemblance to calmodulin. Oncomodulin has been highly conserved across vertebrate evolution (NCBI database) and includes a 40-residue N-terminal domain with a vestigial, inactive Ca2+-binding site (residues 7–33) and a 70-residue consensual EF-hand domain. This latter domain contains one site with relatively low Ca2+ and Mg2+ affinity (residues 41–70) and a high-affinity Ca2+-binding site (residues 81–108).

What is the function of OCM protein?

Given that OCM is a member of the parvalbumin family, is subcellularly compartmentalized, and is prominent in OHCs to the exclusion of other EF-hand Ca2+buffers, its role in the regulation of Ca2+ may be critically important to OHC function. Alternatively, as a Ca2+ sensor, OCM may mediate the activation of Ca2+/calmodulin-dependent phosphorylation of cytoskeletal proteins and/or prestin, leading to changes in OHC stiffness and subsequently changes to motor function. A prior study showed that OCM, a Ca2+-binding protein secreted by a macrophage cell line, is a potent axon-promoting factor for retinal ganglion cells (RGCs). Also in different strains, species, OCM act as a potent growth-promoting signal between the innate immune system and neurons in vivo.

OCM related signaling pathway

Oncomodulin is expressed and secreted by macrophages, that it binds to RGCs with high affinity and that, through a Ca2+/calmodulin (CaM) kinase–dependent pathway, it exerts stronger axon-promoting effects on RGCs than other established trophic factors.

OCM Related Diseases

Given its role in the regulation of Ca2+ may be critically important to OHC function, OCM dysfunction may cause moderate to profound sensorineural hearing loss. Proteins initially found to be exclusive to the inner ear though later identified outside of the inner ear included oncomodulin, OCM was a chance observation during a targeted study based on a global strategy of limited scope.

Case Study 1: Benton Tong, 2016

Fig1. Mean ± SEM hair cell loss at 3 months from wild-type (n = 3) and mutant (n = 3) cochleae.

Case Study 2: Yuqin Yin, 2006

Fig2. OCM contains two active Ca2+-binding sites (rectangles) and is related to α-parvalbumin (α-PV), calmodulin (CM), calbindin (CB) and S100-β in its EF-hand domain, but only to α-PV in its N-terminal region (% sequence identity indicated).

OCM has several biochemical functions, for example, calcium ion binding. Some of the functions are cooperated with other proteins, some of the functions could acted by OCM itself. We selected most functions OCM had, and list some proteins which have the same functions with OCM. You can find most of the proteins on our site.

OCM has direct interactions with proteins and molecules. Those interactions were detected by several methods such as yeast two hybrid, co-IP, pull-down and so on. We selected proteins and molecules interacted with OCM here. Most of them are supplied by our site. Hope this information will be useful for your research of OCM.