Protein kinase C during differentiation of human promyelocytic leukemia cell line, HL‐60

Abstract
Protein kinase C (PKC) from human promyelocytic leukemia HL‐60 cells can be resolved into three fractions (peak a, b and c) by hydroxyapatite column chromatography. Peak a and c enzymes are indistinguishable from the brain type II PKC having β (βI and βII)‐sequence and type III having α‐sequence, respectively. Peak b enzyme is a previously unidentified PKC subspecies that has enzymological properties subtly different from type I (having γ‐sequence), type II and type III PKC. Upon treatment of HL‐60 cells with 1 μM retinoic add, this peak b enzyme is decreased dramatically within 24 h, whilst peak a enzyme (β‐PKC) is increased, and peak c (α‐PKC) enzyme is slightly decreased within 48 h. The result implies that the PKC subspecies in HL‐60 cells have distinct functions during cell differentiation.