High impact information on SRO7

• Furthermore, we demonstrate the formation of a ternary complex of Sec4-GTP, Sro7p, and the t-SNARE Sec9p [1].
• Genetic data support our conclusion that Sro7p functions downstream of Sec4p and further imply that Sro7p and the exocyst share partially overlapping functions, possibly in SNARE regulation [1].
• In this study, we report that the yeast Lgl proteins Sro7p and Sro77p directly interact with Exo84p, which is a component of the exocyst complex that is essential for targeting vesicles to specific sites of the plasma membrane for exocytosis, and that this interaction is important for post-Golgi secretion [2].
• This demonstrates that the primary function of Sro7/77, and likely all members of the lethal giant larvae family, is in exocytosis rather than in regulating the actin cytoskeleton [3].
• Taken together, our studies suggest that members of the lethal giant larvae/tomosyn/Sro7 family play an important role in polarized exocytosis by regulating SNARE function on the plasma membrane [3].

Biological context of SRO7

• SRO7 and SRO77 have redundant functions as loss of both gene products leads to a severe cold-sensitive growth defect that correlates with a severe defect in exocytosis [3].
• Yeast SRO7 was identified as a multicopy suppressor of a defect in Rho3p, a small GTPase that maintains cell polarity [4].
• However, a yeast strain deleted for both SRO7 and its homologue SRO77 exhibits NaCl-induced cell death that is independent on YCA1 [5].
• Cells carrying a sop1Deltasop2Delta double deletion became, however, hypersensitive to Na+ and exhibited increased sensitivity also to Li+ and K+, suggesting involvement of both SOP1 and SOP2 in cation homeostasis [6].
• Mammalian homologues of the Lethal giant larvae (Lgl) tumor suppressor gene have been identified and these homologues can complement the yeast double mutant of Sop1 and Sop2, the yeast homologue of Lgl, as reported previously [7].

Anatomical context of SRO7

• We show that similar to Sec9, Sro7/77 functions in the docking and fusion of post-Golgi vesicles with the plasma membrane [3].
• These results are consistent with a same role for lgl in exocytosis and secretion as that proposed for its yeast ortholog sro7/77 and lgl might function in parallel or independently of its well-documented role in the control of epithelial cell polarity [8].

Associations of SRO7 with chemical compounds

• Whole genome transcriptional profiling showed that in the sni1 mutant, Nonexpresser of PR genes (NPR1)-dependent benzothiadiazole S-methylester-responsive genes were specifically derepressed [9].

Physical interactions of SRO7

• Deletion of the Sro7 tail enables binding to the Qbc SNARE region of Sec9 and this interaction inhibits SNARE complex assembly [10].

Other interactions of SRO7

• Our genetic analysis revealed that deletion of SRO7 and SRO77 showed reciprocal suppression with deletion of MYO1 (i.e., the sro7Delta sro77Delta defect was suppressed by myo1Delta and vice versa) [4].
• We report a novel interaction between Sro7 and the yeast myosin V, Myo2 [11].
• In this study, we describe the identification of a second Sec4p effector, Sro7p, which is a member of the lethal giant larvae tumor suppressor family [1].

Analytical, diagnostic and therapeutic context of SRO7

• Immunolocalization of Sop1p revealed a cytoplasmic distribution and cell fractionation studies showed that a significant fraction of Sop1p was recovered in a sedimentable fraction of the cytosolic material [6].
• Sequence alignments indicate that lethal giant larvae and tomosyn have a two-beta-propeller fold similar to that of Sro7, but only tomosyn appears to retain the regulatory tail [10].

References