Kinase PRKY

Kinase Classification: Group AGC: Family PKA: PRKY

DRAFT DATA

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PRKY kinase

PRKY (Protein Kinase on the Y chromosome) is a copy of the X-chromosome PRKX found only in chimp and human, to date (few primate Y chromosomes have been sequenced). The predicted chimp gene is full length, and has a testis-expressed cloned cDNA (Genbank: AY728014.1)

Human PRKY lacks exon 6 (57 nt in chimp), and in addition has lost the last nucleotide of exon 5. This causes a frameshift and deletion which removes the last 31 AA of the kinase domain and the PKC-Cterminal domain. 10 ESTs and cDNAs confirm the lack of the end of exon 5 and the altered splicing from exon 5 to exon 7. Exon 6 appears to be deleted, since no homology to chimp exon 6 is seen at this locus.

Apart from human and chimp no other PRKY homologs have been found in cDNA/EST databases, whole genome shotgun datasets or in assembled genomes, though Y chromosomes are frequently not sequenced or undersequenced (if the samples are not all male) or are poorly assembled due to their highly repetitive nature. PRKX and PRKY in human are much more similar than either is to rodent PRKX, further indicating that PRKY is a primate-specific duplication of PRKX. Comparison of the chimp and human ORFs upstream of the deleted exon, with PRKX from several primates, suggests weakly that PRKY is not under purifying selection in human, and may even be under positive selection in chimp, though the numbers are very low (Ka/Ks = .0016/0.016 for human branch, 0.017/0.002 for chimp, and 0.019/0.030 for common branch, with Macaque PRKX as an outgroup. PRKX values on the same tree are 0.002/0.035 for human, 0.004/0.018 for chimp and 0.002/0.011 for their common branch).

Gerard 15:17, 15 August 2011 (PDT)