Description

The PIK3CD gene spans a genomic region of 24 coding exons and over 77.17 kb. Transcription The dominant transcript contains two upstream untranslated exons,-2a and-1, as well as an additional first untranslated exon (-2b) identified in the human PIK3CD gene (Kok et al., 2009). Protein Description The PI3K enzymes are a family of activation dependent lipid kinases, which have been divided into three classes (Vanhaesebroeck et al., 1999a). PIK3CD encodes p110delta which belongs to the class I PI3Ks alongside p110alpha, p110beta and p110gamma. The PI3K enzymes are heterodimeric molecules which consist of a catalytic p110 subunit, and a constitutively bound p85 regulatory unit of which there are five isoforms encoded by three genes (PIK3R1, PIK3R2 and PIK3R3) (Vanhaesebroeck and Waterfield, 1999; Geering et al., 2007). The regulatory subunit has a dual function of recruiting the p110 catalytic subunit to an activated upstream tyrosine kinase receptor, and inhibiting catalytic activity in the absence of this stimulatory interaction (Yu et al., 1998). Location of PIK3CD on human chromosome 1