NCKAP5 is short for Nck-associated protein 5, which is also known as the Peripheral clock protein. NCKAP5 is a protein family, which interacts with the SH3-containing region of the adaptor protein Nck. Nck is a protein that interacts with receptor tyrosine kinases and guanine nucleotide exchange factor Sos. The role of Nck can be thought of as similar to Grb2. The role of NCKAP5 is to assist Nck with its adaptor protein role [1].

1: A novel ligand for an SH3 domain of the adaptor protein Nck bears an SH2 domain and nuclear signaling motifs. Matuoka K, Miki H, Takahashi K, Takenawa T; Biochem Biophys Res Commun. 1997;239:488-492. PMID:9344857