Abstract

Actin interacting proteins and protein complexes such as such as CHUP1 (Chloroplast Unusual Positioning 1) and ARP2/3 have been shown to play a role in cellular responses to environmental stimuli as well as plant development. CHUP1 has been shown previously to participate in actin-based chloroplast movement in response to blue light, as well as anchoring the chloroplast to the plasma membrane. The Arp2/3 complex has been demonstrated to participate in trichome and pavement cell development. Furthermore, we have demonstrated that chloroplasts isolated from chup1 and arp3 have a reduced interaction with actin filaments in vitro. In this work, we demonstrate that the chloroplast protein profiles in arp3 and chup1 mutants differ significantly in comparison to wild-type plants. A significant decrease in the RuBisCO small subunit (RbcS) was detected in both mutants when compared to wild-type plants, suggesting that these mutants have altered expression of RbcS or that these mutants have alterations in the translocation of nuclear encoded proteins into the chloroplast