PIPkins1We introduce here the abbreviation PIPkin (an abbreviation we have used in our lab for years) for cogent reasons. Previously, PtdIns4P 5-kinase was the favoured abbreviation, but in view of the extensive revision and uncertainty as to substrates and products that we discuss in this review, only PtdInsP kinase would now suffice. Moreover, we have recently recorded evidence that type II PIPkin is subject to multiple phosphorylations by protein kinases [1]. As we progress in our characterisation of these kinases, we feel that ‘PtdInsP kinase kinases’ is a very confusing term for them, and using PIPkins for PtdInsP kinases (and thus PIPkin kinases for the protein kinases that phosphorylate them) is much to be preferred for general use. A fuller abbreviation, where the reaction catalysed is known, e.g. type I PtdIns4P 5-kinase, is of course a suitable alternative in many instances.1, their substrates and their products: new functions for old enzymes