The RZ family of RGS proteins is less well characterized than the other families. It consists of, RGS17 (also known as RGSZ2), RGS19 (also known as GAIP) and RGS20 (with several splice variants including RGSZ1 and Ret-RGS). All members contain an N-terminal cysteine string motif [3] which is a site of palmitoylation and could serve functions in membrane targeting, protein stability or aid protein-protein interactions [1,3]. However, the function in the case of RZ family RGS proteins is not yet fully understood. Members of the RZ family of RGS proteins are the only RGS proteins that have selective GAP activity for Gα_z, a function that resulted in the name of the family [2,4-6]. However, the members of the RZ family are able to also GAP Gα_i/o members with varying selectivity.

1. Ajit SK, Ramineni S, Edris W, Hunt RA, Hum WT, Hepler JR, Young KH. (2007) RGSZ1 interacts with protein kinase C interacting protein PKCI-1 and modulates mu opioid receptor signaling. Cell Signal, 19 (4): 723-30. [PMID:17126529]

2. Glick JL, Meigs TE, Miron A, Casey PJ. (1998) RGSZ1, a Gz-selective regulator of G protein signaling whose action is sensitive to the phosphorylation state of Gzalpha. J Biol Chem, 273 (40): 26008-13. [PMID:9748279]

3. Linder ME, Deschenes RJ. (2007) Palmitoylation: policing protein stability and traffic. Nat Rev Mol Cell Biol, 8 (1): 74-84. [PMID:17183362]

4. Mao H, Zhao Q, Daigle M, Ghahremani MH, Chidiac P, Albert PR. (2004) RGS17/RGSZ2, a novel regulator of Gi/o, Gz, and Gq signaling. J Biol Chem, 279 (25): 26314-22. [PMID:15096504]

5. Wang J, Ducret A, Tu Y, Kozasa T, Aebersold R, Ross EM. (1998) RGSZ1, a Gz-selective RGS protein in brain. Structure, membrane association, regulation by Galphaz phosphorylation, and relationship to a Gz gtpase-activating protein subfamily. J Biol Chem, 273 (40): 26014-25. [PMID:9748280]

6. Wong YH, Conklin BR, Bourne HR. (1992) Gz-mediated hormonal inhibition of cyclic AMP accumulation. Science, 255 (5042): 339-42. [PMID:1347957]