In the active conformation, PKCs bind a variety of interactors  – adaptors or scaffolds, binding partners that can also be substrates and others in order to fulfill many cellular tasks. Among adaptors are Rack1 and 2 as well as Pick1. Others include Fyn, pericentrin, fascin, Lck and Btk of which the last three are also substrates in that they need to be PKC-phosphorylated to be activated. In the case of Btk, mutual phosphorylation controls the activities of both kinases: PKC-phosphorylated and activated Btk provides a negative feedback relay that inhibits PKC. For more details see references PMID 15380937, 11607837, 18491053. The interactors are listed by PKC group with aliases in parentheses, full names and links to gene report pages:

cPKC
Gnb2l1 (Rack1, guanine nucleotide binding protein (Gprotein), beta polypeptide 2-like 1) – receptor for activated C kinase 1
Pick1 – protein interacting with PRKCA 1
Fscn3 (fascin 3) – fascin actin-bundling protein 3
PCNT  (kendrin, Sckl4) – pericentrin (human gene)

nPKC
Rack1  (Gnb2l1) – receptor for activated C kinase 1
Copb1 (Rack2) – coatomer protein complex, subunit beta 1
Ldb3 (Zasp, Cypher) – LIM domain binding 3
Fyn (Slk) – FYN proto-oncogene, Src family tyrosine kinase
Lck (lymphocyte-specific protein tyrosine kinase) – LCK proto-oncogene, Src family tyrosine kinase
Btk (Bruton agammaglobulinemia tyrosine kinase) – Bruton tyrosine kinase

aPKC
Pard3 (ASIP, Bazooka) – par-3 family cell polarity regulator
Pard6a (Par6, Par-6a, PAR-6 alpha) – par-6 family cell polarity regulator alpha
Pard6b – par-6 family cell polarity regulator beta
Pard6g – par-6 family cell polarity regulator gamma