A yeast gene coding for a putative protein kinase homologous to cdc25 suppressing protein kinase

Abstract
A yeast gene termed YKR coding for a putative protein kinase was isolated by using the cloned cDNA for rabbit protein kinase C as a hybridization probe. The encoded protein (YKR), composed of 380 amino acid residues, shows extensive sequence homology to serine/threonine‐specific protein kinases from various species in the approx. 320 C‐terminal amino acid residues, strongly suggesting that YKR is endowed with a protein kinase activity. The observed homologies to the cdc25 suppressing protein kinase from yeast, the catalytic subunit of mammalian cAMP‐dependent protein kinase, and mammalian protein kinase C were 76, 48 and 37%, respectively. Gene replacement experiments showed that YKR itself is not essential for cell proliferation.