Possible role of alteration in pH, but not in ionic strength, in the modulation of Ca2 ‐dependent and diacylglycerol‐induced association of protein kinase C‐α with plasma membrane

In an attempt to elucidate the mechanism of the membrane binding of protein kinase C‐α (PKC‐α), effects of pH and ionic strength were examined on Ca2+‐dependent and diacylglycerol‐induced association of this PKC with rat liver plasma membrane. In the absence of diacylglycerol, the membrane‐bound PKC‐α increased according to the changes in pH from 6 to 8. However, these reactions were not seriously influenced by alterations in ionic strength (0‐240 mM NaCl). In the presence of diacylglycerol, this pH‐modulated binding of PKC‐α to plasma membrane was more effective under lower Ca2+ concentration at pH 8. These results suggest that alkaline pH conditions seem to be important for preferable association of PKC‐α with plasma membrane.