N-terminal EF-hand calcium-binding protein 3 is a protein that in humans is encoded by the NECAB3 gene.

The protein encoded by this gene interacts with the amino-terminal domain of the neuron-specific X11-like protein (X11L), inhibits the association of X11L with amyloid precursor protein through a non-competitive mechanism, and abolishes the suppression of beta-amyloid production by X11L. This protein, together with X11L, may play an important role in the regulatory system of amyloid precursor protein metabolism and beta-amyloid generation. The protein is phosphorylated by NIMA-related expressed kinase 2, and localizes to the Golgi apparatus. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jul 2008].
Function: Inhibits the interaction of APBA2 with beta-amyloid precursor protein (APP), and hence allows formation of beta-amyloid.