We have previously shown that the conventional PKC alpha can read out Ca waves, spatially restricted Ca signals and elementary Ca signals. Here we present novel insights into the cPKC-membrane interactions obtained from an analysis of a large population of local translocation events (160 LTEs; 60 locations, 18 cells) recorded by realtime confocal microscopy of cPKC translocations in living cells. We found two entities of LTEs. (i) LTEs with a brief lifetime (down to <500 ms) and highly restricted lateral spread (down to < 1 mm) and (ii) LTEs with an extended lifetime (>6 s) which lateral spreads and amplitudes were largely restricted (3–4 mm). The spatio-temporal properties of the latter LTEs indicated that they displayed a two-step activation mechanism. Surprisingly, those LTEs did not continue to spatially expand for lifetimes exceeding 1s. From our results we conclude that these groups of LTEs represent two different modes of cPKC-membrane interactions: briefer LTEs correspond to shortlived, Ca-C2-domain-mediated cPKC-membrane interactions during which the cPKC apparently probes the inner leaflet of the plasma membrane. The longerlived LTEs reflect C1-domain-mediated extended cPKC-DAG or cPKC-target protein interactions. This notion was supported in experiments with cPKCs containing mutated C1 (no DAG binding) and/or C2 (no Ca binding) domains. The project was funded in part by HOMFOR, DFG SFB530 TP B6 and HBFG.