Acts as component of the Sec62/63 complex which is involved in SRP-independent post-translational translocation across the endoplasmic reticulum (ER) and functions together with the Sec61 complex and KAR2 in a channel-forming translocon complex. A cycle of assembly and disassembly of Sec62/63 complex from SEC61 may govern the activity of the translocon. SEC63 may affect SEC1-polypeptide interactions by increasing the affinity of targeting pathways for SEC61 and/or by modifying SEC61 to allow more efficient polypeptide interaction. May also be involved in SRP-dependent cotranslational translocation. Is essential for cell growth and for germination. Component of the heterotetrameric Sec62/63complex composed of SEC62, SEC63, SEC66 and SEC72. The Sec62/63 complex associates with the Sec61 complex to form the Sec complex. SEC63 interacts in its phosphorylated form with SEC62. May physically associate with KAR2 in the endoplasmic reticulum and this interaction may be regulated by ATP hydrolysis. Part of a complex consisting of KAR2, SEC63, SEC66 and SEC72. Phosphotylated by casein kinase II. Present with 17700 molecules/cell in log phase SD medium.