Characterization of a cis-Golgi matrix protein, GM130.

Abstract

Abstract. Antisera raised to a detergent-and salt-resistant matrix fraction from rat liver Golgi stacks were used to screen an expression library from rat liver cDNA. A full-length clone was obtained encoding a protein of 130 kD (termed GM130), the COOH-terminal domain of which was highly homologous to a Golgi human auto-antigen, golgin-95 (Fritzler et al., 1993). Biochemical data showed that GM130 is a peripheral cytoplasmic protein that is tightly bound to Golgi membranes and part of a larger oligomeric complex. Predictions from the protein sequence suggest that GM130 is an extended rod-like protein with coiled-coil domains. Immunofluorescence microscopy showed partial overlap with medial-and trans-Golgi markers but almost complete overlap with the cis-Golgi network (CGN) marker, syntaxin5. Immunoelectron microscopy confirmed this location showing that most of the GM130 was located in the CGN and in one or two cisternae on the cis-side of the Golgi stack. GM130 was not re-distributed to the ER in the presence of brefeldin A but maintained its overlap with syntaxin5 and a partial overlap with the ER-Golgi intermediate compartment marker, p53. Together these results suggest that GM130 is part of a cis-Golgi matrix and has a role in maintaining cis-Golgi structure.

Bap31 Is an Itinerant Protein That Moves between the Peripheral Endoplasmic Reticulum (ER) and a Juxtanuclear Compartment Related to ER-associated Degradation

“…GM130 is one of the fast-moving proteins during BFA recovery (Jiang et al, 2006). As reported previously (Nakamura et al, 1995;Seemann et al, 2000;Ward et al, 2001), GM130 was distributed in punctate structures in BFA-treated cells (Supplemental Figure S3, second row). Although previous studies showed that combined treatment of normal rat kidney or HeLa cells with BFA followed by BFA plus H89 causes ER localization of GM130 (Puri and Linstedt, 2003;Jiang et al, 2006), such redistribution was not observed in COS-7 cells when 50 M H89 in addition to 10 M BFA was used (data not shown).…”

“…As shown in Supplemental Figure S2, in Noc-treated cells, Bap31 did not accumulate at ER exit sites defined by Sec31A (third row), but remained within the ER where SERCA2 was present (second row) upon H89 treatment. H89 treatment did not affect the exit site localization of ␤-COP (fourth row) or a Golgi marker, GM130 (Nakamura et al, 1995) (bottom row), in Noc-treated cells. These results sup- port the idea that the transport of Bap31 occurs not through the conventional transport pathway.…”

Germinal center kinases in immune regulation

“…[91][92][93] The very C-terminus of GM130 may bind to and stimulate the catalytic activity of HtrA1, a serine protease that inhibits TGF-b signaling. 94 EspG proteins produced by enteric pathogens may interact with GM130 and disrupt protein secretion of the host cells.…”

Biogenesis of Golgi Stacks in Imaginal Discs ofDrosophila melanogaster

“…The rabbit polyclonal MLO7 antibody (gift from M. Lowe, Manchester, United Kingdom) was raised against the first 73 amino acids of human GM130 (Nakamura et al, 1995;Lowe et al, 1998), a Golgi peripheral membrane protein receptor for p115 (Nakamura et al, 1997, see below). The corresponding 73 amino acids in the predicted Drosophila homolog of GM130 (AJ276417, CG11061) are 40% identical and 51% similar to human and rat GM130 with a very strong conservation in the first 25 (up to 64% identity and 84% similarity).…”