SQSTM1/p62 (sequestosome 1) is an important receptor protein involved in many cellular signaling processes, including macroautophagy/autophagy. It is a molecular hub for cellular homeostasis and cellular responses. Within autophagy, SQSTM1 targets ubiquitinated cargo for degradation, maintaining cellular proteostasis. Structurally, SQSTM1 consists of several domains that facilitate its binding to ubiquitinated cargo, the formation of SQSTM1 aggregate inclusions, interactions with MAP1LC3/LC3, and the mediation of clearance via the autophagy pathway. Beyond its structure, post-translational modifications of SQSTM1 dynamically regulate its function within a cell. Post-translational modifications - such as phosphorylation, ubiquitination, acetylation, S-acylation, and S-nitrosylation - are crucial for regulating SQSTM1 function, localization, and interaction with autophagic components, thereby influencing SQSTM1's role in the autophagy pathway. Understanding the role of these protein modifications in modulating autophagy may provide better insight into developing therapeutic strategies for diseases with dysregulated autophagy, such as neurodegenerative diseases. This review will discuss the role of these post-translational modifications in controlling SQSTM1's localization and function in autophagy.Abbreviations: ABHD = α/β-hydrolase domain; AD = Alzheimer Disease; ALS = amyotrophic lateral sclerosis; ATG = autophagy related ; CSNK2/CK2 = casein kinase 2; HD = Huntington Disease; HDAC/KDAC = histone deacetylase/lysine deacetylase; HTT = huntingtin; KAT = lysine acetyltransferase; KEAP1 = kelch like ECH associated protein 1; KIR = KEAP1-interacting region; LIR = LC3-interacting region; LYPLA/APT = lysophospholipase/acyl-protein thioesterase; MAP1LC3/LC3 = microtubule associated protein 1 light chain 3; MEF = mouse embryonic fibroblast; mHTT = mutant huntingtin; MTORC1 = MTOR complex 1; NBR1 = NBR1 autophagy cargo receptor; NEDD4 = NEDD4 E3 ubiquitin protein ligase ; NO = nitric oxide; NFE2L2/Nrf2 = nuclear factor erythroid 2-factor 2; PAT = palmitoyl acyltransferase; PB1 = Phox-BEM1 domain; PE = phosphatidylethanolamine; PLEKHM1 = pleckstrin homology and RUN domain containing M1; PLK2 = polo like kinase 2; PRKA/PKA = protein kinase cAMP-activated; PPT1 = palmitoyl-protein thioesterase 1; RB1CC1 = RB1 inducible coiled-coil 1; SNCA/α-synuclein = synuclein alpha; SNO = S-nitrosothiol; SOD1 = superoxide dismutase 1; SQSTM1 = sequestosome 1; TARDBP/TDP-43 = TAR DNA binding protein ; TBK1 = TANK binding kinase 1; TAX1BP1 = Tax1 binding protein 1; TRIM = tripartite motif containing ; UBA = ubiquitin-associated domain; UBE = ubiquitin-conjugating enzyme; ULK1 = unc-51 like autophagy activating kinase 1; UPS =ubiquitin-proteasome system; USP8 = ubiquitin specific peptidase 8; ZDHHC = zDHHC palmitoyltransferase.
