PRKCA and type 1 diabetes mellitus: PKCα inhibitor stabilizes nephrin expression and ameliorates the proteinuria in streptozocin-induced type 1 diabetic mice Genetic loss of PKCα and PKCβ reduce the proteinuria in streptozocin-induced type 1 diabetic mice Dual PKCα and PKCβ inhibitor ameliorate the proteinuria in the streptozocin-induced type 1 diabetic mice and db/db type 2 diabetic mice