Alternative titles; symbols
HGNC Approved Gene Symbol: PPP1R7
Cytogenetic location: 2q37.3 Genomic coordinates (GRCh38): 2:241,149,573-241,183,652 (from NCBI)
Type 1 serine/threonine phosphatases consist of a catalytic subunit and one or more regulatory subunits. The noncatalytic subunits not only determine the activity and substrate specificity of the holoenzyme, but also target the phosphatase to a particular cellular location. S. pombe sds22 is a regulatory polypeptide of protein phosphatase-1 that is required for the completion of mitosis. By sequence analysis of a human brain expressed sequence tag (EST) that is homologous to sds22, and by 5-prime RACE using oligonucleotides based on this EST, Renouf et al. (1995) determined the complete cDNA sequence of a human homolog of sds22, termed PPP1R7. The predicted 360-amino acid PPP1R7 protein contains 11 leucine-rich repeats, which may participate in protein-protein interactions, and multiple putative phosphorylation sites. The amino acid sequences of PPP1R7 and sds22 are 46% identical. Western blot analysis using antibodies against human PPP1R7 detected a 44-kD protein in both the cytoplasm and nucleus of rat liver cells. Northern blot analysis showed a major 1.4-kb transcript in all human tissues examined.
Rodrigues et al. (2015) studied division in proliferating Drosophila and human cells and demonstrated the existence of a signaling pathway that triggers the relaxation of the polar cell cortex at mid anaphase. This is independent of furrow formation, centrosomes, and microtubules and instead depends on PP1 phosphatase (176875) and its regulatory subunit Sds22. As separating chromosomes move towards the polar cortex at mid anaphase, kinetochore-localized PP1-Sds22 helps to break cortical symmetry by inducing the dephosphorylation and inactivation of ezrin (123900)/radixin (179410)/moesin (309845) proteins at cell poles. This promotes local softening of the cortex, facilitating anaphase elongation and orderly cell division. Rodrigues et al. (2015) concluded that their study identified a conserved kinetochore-based phosphatase signal and substrate, which function together to link anaphase chromosome movements to cortical polarization, thereby coupling chromosome segregation to cell division.
By PCR analysis of YACs and somatic cell hybrid DNAs using sequence tagged sites derived from the 3-prime untranslated region of PPP1R7, Berry et al. (1995) mapped the PPP1R7 gene to 2q37.3.
Berry, R., Stevens, T. J., Walter, N. A. R., Wilcox, A. S., Rubano, T., Hopkins, J. A., Weber, J., Goold, R., Soares, M. B., Sikela, J. M. Gene-based sequence-tagged-sites (STSs) as the basis for a human gene map. Nature Genet. 10: 415-423, 1995. [PubMed: 7670491] [Full Text: https://doi.org/10.1038/ng0895-415]
Renouf, S., Beullens, M., Wera, S., Van Eynde, A., Sikela, J., Stalmans, W., Bollen, M. Molecular cloning of a human polypeptide related to yeast sds22, a regulator of protein phosphatase-1. FEBS Lett. 375: 75-78, 1995. [PubMed: 7498485] [Full Text: https://doi.org/10.1016/0014-5793(95)01180-m]
Rodrigues, N. T. L., Lekomtsev, S., Jananji, S., Kriston-Vizi, J., Hickson, G. R. X., Baum, B. Kinetochore-localized PP1-Sds22 couples chromosome segregation to polar relaxation. Nature 524: 489-492, 2015. [PubMed: 26168397] [Full Text: https://doi.org/10.1038/nature14496]