GTPv2, defined in 3GPP TS 29.274, is dramatically different from GTPv1, defined in 3GPP TS 29.060.
GTPv2-C is the control layer messaging for GTPv2. It is used by LTE mobile stations, SGSN units for backwards compatibility, and SGWs that are the gateway to other networks. In general the SGW manages the user data (GTP-U) and communicates with GTP-C via S11 with the MME for mobility management and with GTP-C via S5/S8 with the PGW for tunnel management. Also GTP (S2b in EMEA) is used between ePDG and PGW for VoWifi.
For more information about GTPv2, see GTPv2 - evolving packet core architecture.