High impact information on GOLPH4

• Furthermore, two proteins whose Golgi targeting depends on endosome-to-Golgi retrieval in the bypass pathway accumulated in early/recycling endosomes in the absence of GPP130 [1].
• An RNA interference-based test revealed that GPP130 was required for efficient exit of Shiga toxin B-fragment from endosomes en route to the Golgi apparatus [1].
• The use of lumenal determinants for both basolateral cycling and endosome-to-Golgi retrieval suggests that a novel receptor-mediated mechanism operates at both the trans-Golgi network and distal sites to sort GPP130 along the late-endosome-bypass retrieval pathway in polarized cells [2].
• Golgi phosphoprotein of 130 kDa (GPP130) is a cis-Golgi protein that allows assay of retrieval-based targeting because it redistributes to endosomes upon treatment with agents that disrupt lumenal pH, and it undergoes endosome-to-Golgi retrieval upon drug removal [3].
• Because monensin blocks endosome-to-Golgi transport, the finding that the endosomal determinant confers monensin sensitivity suggests that the endosomal determinant causes GPP130 to traffic to endosomes from which it is normally retrieved [3].

Anatomical context of GOLPH4

• Analysis of chimeric molecules containing domains from GPP130 and the plasma membrane protein dipeptidylpeptidase IV indicated that GPP130 targeting information is contained entirely within its lumenal domain [3].
• In vivo recordings were made from the somatosensory cortex from postnatal day (P) 55 to P138, in response to electrical stimulation of the infraorbital nerve supplying the mystacial whiskers [4].

Associations of GOLPH4 with chemical compounds

• In contrast to the behavior of previously studied type II Golgi proteins, overexpression of GPP130 led to a pronounced accumulation in endocytotic vesicles, and endogenous GPP130 reversibly redistributed to endocytotic vesicles after chloroquine treatment [5].
• Unlike the TGN marker TGN38/46, GPP130 and GP73 colocalized in the early Golgi and redistributed to the ER after brefeldin A treatment [6].

Other interactions of GOLPH4

• Although GP73 did not associate with GPP130, its steady-state Golgi targeting was also mediated by a lumenal predicted coiled-coil stem domain [6].

References