[4] The APC protein is a negative regulator that controls beta-catenin concentrations and interacts with E-cadherin, which are involved in cell adhesion.

The protein made by the APC gene plays a critical role in several cellular processes that determine whether a cell may develop into a tumor.

It is not known if this large predicted unstructured region from amino acid 800 to 2843 persists in vivo or would form stabilised complexes – possibly with yet unidentified interacting proteins.

[9] Recently, it has been experimentally confirmed that the mutation cluster region around the center of APC is intrinsically disordered in vitro.

[5] Familial adenomatous polyposis (FAP) is caused by an inherited, inactivating mutation in the APC gene.

[6] Another mutation is carried by approximately 6 percent[citation needed] of people of Ashkenazi (eastern and central European) Jewish heritage.

This mutation results in the substitution of the amino acid lysine for isoleucine at position 1307 in the APC protein (also written as I1307K or Ile1307Lys).

[14] The (Adenomatous Polyposis Coli) APC protein normally builds a "destruction complex" with glycogen synthase kinase 3-alpha and or beta (GSK-3α/β) and Axin via interactions with the 20 AA and SAMP repeats.

[19] The deactivation of the APC protein can take place after certain chain reactions in the cytoplasm are started, e.g. through the Wnt signals that destroy the conformation of the complex.

Mutations in APC lead to loss of β-catenin regulation, altered cell migration and chromosome instability.

[11] Rosenberg et al. found that APC directs cholinergic synapse assembly between neurons, a finding with implications for autonomic neuropathies, for Alzheimer's disease, for age-related hearing loss, and for some forms of epilepsy and schizophrenia.