2001 Volume 129 Issue 4 Pages 551-560
The different oligomers composing the high molecular weight calcium/calmodulin-dependent protein kinase II (CaMKII) holoenzyme, previously shown to be transiently activated during Xenopus oocyte maturation, migrate on SDS-PAGE as proteins of 83, 72, 62, 56, and 52 kDa and have all been cloned. The holoenzyme consists of the CaMKII isoforms γB, γC, and δ12, already described in other species, while γJ, γK, γL, γM, and γN are now described for the first time. The γ-isoforms are splice variants of the γ-gene, containing in their variable region different combinations of known exons and one, two or three novel exons. Semi-quantitative RT-PCR revealed that all isoforms identified in prophase oocytes are also expressed in adult tissues with a tissue-specific expression pattern. At least thirty different CaMKII isoforms could be identified in different Xenopus adult tissues, most of which are described here for the first time.
