ZC3HC1

NIPA is broadly expressed in the human tissues, with the highest expression in heart, skeletal muscle, and testis.[11] It is a human F-box protein that defines an SCF-type ubiquitin E3 ligase, the formation of which is regulated by cell-cycle-dependent phosphorylation of NIPA. Cyclin B1, essential in the entry into mitosis, is targeted by SCFNIPA in interphase. Phosphorylation of NIPA occurs in G2 phase, results in dissociation of NIPA from the SCF core, and has been proven critical for proper G2/M transition.[8] Oscillating ubiquitination of nuclear cyclin B1 driven by the SCFNIPA complex contributes to the timing of mitotic entry.[9][14] NIPA is also reported to delay apoptosis and the localization of NIPA is required for this antiapoptotic function.[11]

Model organisms have been used in the study of ZC3HC1 function. A conditional knockout mouse line, called Zc3hc1^{tm1a(KOMP)Wtsi}[28][29] was generated as part of the International Knockout Mouse Consortium program — a high-throughput mutagenesis project to generate and distribute animal models of disease to interested scientists.[30][31][32]

Male and female animals underwent a standardized phenotypic screen to determine the effects of deletion.[26][33] Twenty two tests were carried out on mutant mice and eleven significant abnormalities were observed.[26] Fewer than expected homozygous mutant mice were identified at weaning. Mutants appear to be subfertile, had decreased vertical activity in an open field, decreased lean body mass, decreased rib number and decreased mature B cell number. Males also had a decreased body weight, an abnormal posture and atypical indirect calorimetry data. Females also had an abnormally short snout and atypical haematology parameters .[26]

In humans, NIPA has been implicated in cardiovascular diseases by genome-wide association (GWAS) studies. Specifically, a single-nucleotide polymorphism (SNP) situated in ZC3HC1 has been shown to predict coronary artery disease.[34][35] This prediction appears to be independent of traditional risk factors for cardiovascular disease such as high cholesterol levels, high blood pressure, obesity, smoking and diabetes mellitus, which are primary targets of current treatments for coronary artery disease. Therefore, studying the function of this gene may identify novel pathways contributing to coronary artery disease that result in the development of novel therapeutics.